Trigonometry worksheet for finding trigonometric ratios in right triangles and using a calculator for angle values.
Worksheet titled "Finding Trigonometric Ratios" with six right triangles labeled A, B, C, X, Y, Z, each with side lengths, asking to find sine, cosine, and tangent values for specific angles, plus two calculator-based problems for sin 77° and tan 17°.
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Show Answer Key & Explanations
Step-by-step solution for: Trigonometric Ratios Worksheets - Math Monks
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Show Answer Key & Explanations
Step-by-step solution for: Trigonometric Ratios Worksheets - Math Monks
Let’s solve each problem step by step. We’ll use the definitions of sine, cosine, and tangent in right triangles:
- sin(θ) = opposite / hypotenuse
- cos(θ) = adjacent / hypotenuse
- tan(θ) = opposite / adjacent
We must identify which side is opposite, adjacent, or hypotenuse relative to the angle given.
---
Problem 1: sin C in triangle ABC (right angle at B)
Triangle ABC:
- Right angle at B → so AC is hypotenuse = 50
- Angle C is at vertex C
- Side opposite to angle C is AB = 14
- So, sin C = opposite/hypotenuse = 14/50 = 7/25 = 0.28
✔ Check: 14 ÷ 50 = 0.28 — correct.
---
Problem 2: sin Z in triangle XYZ (right angle at X)
Triangle XYZ:
- Right angle at X → so YZ is hypotenuse = 40
- Angle Z is at vertex Z
- Side opposite to angle Z is XY = 24
- So, sin Z = opposite/hypotenuse = 24/40 = 3/5 = 0.6
✔ Check: 24 ÷ 40 = 0.6 — correct.
---
Problem 3: tan A in triangle ABC (right angle at B)
Triangle ABC:
- Right angle at B → so AC is hypotenuse? Wait — actually, sides are labeled: CA=29, CB=21, BA=20, right angle at B.
→ So legs are AB = 20 and BC = 21; hypotenuse is AC = 29.
Angle A is at vertex A.
Opposite to angle A is BC = 21
Adjacent to angle A is AB = 20
So tan A = opposite/adjacent = 21/20 = 1.05
✔ Check: 21 ÷ 20 = 1.05 — correct.
---
Problem 4: tan B in triangle ABC (right angle at A)
Triangle ABC:
- Right angle at A → so BC is hypotenuse = 50
Legs: AB = 40, AC = 30
Angle B is at vertex B.
Opposite to angle B is AC = 30
Adjacent to angle B is AB = 40
So tan B = opposite/adjacent = 30/40 = 3/4 = 0.75
✔ Check: 30 ÷ 40 = 0.75 — correct.
---
Problem 5: cos X in triangle XYZ (right angle at Y)
Triangle XYZ:
- Right angle at Y → so XZ is hypotenuse = 29
Legs: XY = 21, YZ = 20
Angle X is at vertex X.
Adjacent to angle X is XY = 21
Hypotenuse is XZ = 29
So cos X = adjacent/hypotenuse = 21/29 ≈ ?
Let’s calculate: 21 ÷ 29 = 0.724137... → but we don’t need decimal yet unless asked. The question doesn’t specify format, but since others are fractions or decimals, let’s leave as fraction unless calculator needed later. But wait — problems 7 and 8 say “use calculator”, so maybe these first six can be exact fractions.
But looking back: Problem 5 says “cos X = ___” — no instruction to round, so we can write exact value.
21/29 is already simplified.
But let me check if they want decimal? No — only 7 and 8 say “use calculator”. So for 1–6, exact values are fine.
Wait — problem 6 also doesn’t say calculator. So we’ll keep fractions where possible.
But let’s see what’s expected. In problem 1, 14/50 reduces to 7/25. Similarly here, 21/29 is simplest form.
Actually, let’s double-check labeling:
Triangle XYZ: right angle at Y → points X, Y, Z.
Side XY = 21, YZ = 20, XZ = 29.
Angle X: between sides XY and XZ.
Adjacent to angle X: XY = 21
Opposite: YZ = 20
Hypotenuse: XZ = 29
Yes, cos X = adjacent/hypotenuse = 21/29
✔ Correct.
---
Problem 6: cos C in triangle ABC (right angle at B)
Triangle ABC:
- Right angle at B → so AC is hypotenuse = 15
Legs: AB = 9, BC = 12
Angle C is at vertex C.
Adjacent to angle C is BC = 12
Hypotenuse is AC = 15
So cos C = adjacent/hypotenuse = 12/15 = 4/5 = 0.8
✔ Check: 12 ÷ 15 = 0.8 — correct.
---
Now Problems 7 and 8 require calculator, rounded to nearest ten-thousandth (4 decimal places).
Problem 7: sin 77°
Using calculator: sin(77) ≈ 0.974370064...
Rounded to 4 decimal places: look at fifth digit → 7, so round up fourth digit from 3 to 4? Wait:
0.97437 → digits after decimal: 9 (tenths), 7 (hundredths), 4 (thousandths), 3 (ten-thousandths), 7 (hundred-thousandths)
So ten-thousandths place is the 4th decimal: currently 3, next digit is 7 ≥ 5 → round up → 0.9744
✔ sin 77° ≈ 0.9744
---
Problem 8: tan 17°
Calculator: tan(17) ≈ 0.305730681...
Digits: 0.30573...
Ten-thousandths place is 4th decimal: 7, next digit is 3 < 5 → do not round up.
So tan 17° ≈ 0.3057
✔ Confirmed.
---
Final Answers:
1. sin C = 14/50 = 7/25 → but usually written as decimal or reduced fraction. Since 14/50 reduces to 7/25, and 7/25 = 0.28, either is acceptable. But in context, probably decimal or simplified fraction. Looking at other answers, some are decimals. Let's go with simplified fraction unless specified.
Wait — problem 1: 14/50 simplifies to 7/25. But 7/25 is 0.28 exactly. Either is fine. I'll write as fraction unless decimal is clearer.
But in school worksheets, often they accept both. However, since problem 6 gives 12/15 which reduces to 4/5, likely they expect simplified fractions.
But let’s check problem 2: 24/40 = 3/5 = 0.6 — again, same.
To be safe, I’ll provide simplified fractions for 1–6, and decimals for 7–8 as instructed.
But problem 3: 21/20 is improper fraction — that’s okay.
Alternatively, maybe they want decimals for all? But 7 and 8 specifically say “use calculator”, implying others may not need it.
Looking at the worksheet layout, blanks are just lines — no specification. But in math class, for exact values, fractions are preferred.
However, let’s see: in problem 1, 14/50 = 0.28 exactly — so decimal is fine.
I think for consistency, since 7 and 8 require decimals, and others can be exact, I’ll write exact values (fractions or whole numbers) for 1–6, and decimals for 7–8.
But let me verify standard practice: in trig ratios, if it’s a nice decimal, sometimes they write decimal. But 21/29 is not nice, so fraction is better.
Actually, re-examining: problem 5 is 21/29 — that’s approximately 0.7241, but since no calculator instruction, leave as fraction.
Similarly, problem 3: 21/20 = 1.05 — that’s exact decimal.
Hmm. To avoid confusion, I’ll present all answers in the most appropriate form:
- If it simplifies to a terminating decimal, use decimal.
- Otherwise, use fraction.
- For 7 and 8, use decimal as instructed.
So:
1. sin C = 14/50 = 0.28 → 0.28 (since it terminates)
2. sin Z = 24/40 = 0.6 → 0.6
3. tan A = 21/20 = 1.05 → 1.05
4. tan B = 30/40 = 0.75 → 0.75
5. cos X = 21/29 → this does not terminate, so 21/29 (but wait, is that acceptable? Maybe they expect decimal? But no calculator instruction. I think fraction is fine.)
- However, looking at the worksheet, all blanks are equal size, and 21/29 might be messy. Perhaps I should compute it? But instructions say only 7 and 8 use calculator.
- Actually, let me check: in many textbooks, for such problems, if it’s not a nice number, they leave as fraction. But 21/29 is about 0.7241, but without calculator, student might not know.
- Wait — perhaps I made a mistake? Is there a way it simplifies? 21 and 29 share no common factors (29 is prime), so 21/29 is simplest.
But let’s see problem 6: 12/15 = 0.8 — nice decimal.
Perhaps for consistency, since 1-4 and 6 give nice decimals, and 5 does not, but the problem doesn't specify, I'll write 21/29 for problem 5.
However, upon second thought, in the context of "finding trigonometric ratios" with given side lengths, and no mention of calculator for 1-6, the expected answer is likely the ratio as a fraction or simplified form.
But to match the style, let's see: in problem 1, 14/50 could be left as is, but usually simplified.
I recall that in such worksheets, they often expect the ratio in simplest form, whether fraction or decimal.
For problem 5, 21/29 is already simplified, so I'll keep it as fraction.
But let's confirm with calculation: 21 divided by 29 is approximately 0.7241, but since no calculator, fraction is better.
Actually, I think I should provide the exact value as per definition.
Final decision:
- Problems 1-6: exact values (simplified fractions or decimals if terminating)
- Problems 7-8: decimals to 4 places
So:
1. sin C = 14/50 = 7/25 or 0.28 — I'll use 0.28 since it's exact and simple.
2. sin Z = 24/40 = 3/5 = 0.6
3. tan A = 21/20 = 1.05
4. tan B = 30/40 = 3/4 = 0.75
5. cos X = 21/29 — leave as fraction
6. cos C = 12/15 = 4/5 = 0.8
7. sin 77° = 0.9744
8. tan 17° = 0.3057
But for problem 5, if I write 21/29, is that acceptable? Yes.
To be thorough, let's list all:
After careful consideration, I'll present:
1. 0.28
2. 0.6
3. 1.05
4. 0.75
5. \frac{21}{29} (but since the blank is for a number, perhaps decimal? But no calculator. I think fraction is fine.)
Wait — looking back at the user's image description, it's a worksheet with blanks, and for 7 and 8, it specifies "use calculator", implying for 1-6, you can do it without, so fractions are expected for non-terminating.
But 21/29 is not nice, but it's correct.
Perhaps I can write it as a decimal approximation? But that would be inconsistent.
Another idea: maybe I miscalculated which sides are which.
In problem 5: triangle XYZ, right angle at Y.
Points: X, Y, Z.
Sides: XY = 21, YZ = 20, XZ = 29.
Angle at X: so from X, the sides are to Y and to Z.
The side adjacent to angle X is XY = 21 (since it's next to X and not the hypotenuse).
The hypotenuse is XZ = 29.
Yes, cos X = adjacent/hypotenuse = 21/29.
Correct.
I think it's fine.
For the final answer, I'll write:
1. 0.28
2. 0.6
3. 1.05
4. 0.75
5. \frac{21}{29}
6. 0.8
7. 0.9744
8. 0.3057
But since the output should be plain text, for problem 5, I'll write "21/29".
Similarly, others as decimals or fractions.
To make it uniform, perhaps convert all to decimals where possible, but for 5, it's irrational? No, it's rational but repeating? 21/29 = 0.724137931... repeating, so not terminating.
So best to leave as fraction.
Final Answer:
1. 0.28
2. 0.6
3. 1.05
4. 0.75
5. 21/29
6. 0.8
7. 0.9744
8. 0.3057
But let's write them in order as per the problems.
──────────────────────────────────────
Final Answer:
1. 0.28
2. 0.6
3. 1.05
4. 0.75
5. 21/29
6. 0.8
7. 0.9744
8. 0.3057
- sin(θ) = opposite / hypotenuse
- cos(θ) = adjacent / hypotenuse
- tan(θ) = opposite / adjacent
We must identify which side is opposite, adjacent, or hypotenuse relative to the angle given.
---
Problem 1: sin C in triangle ABC (right angle at B)
Triangle ABC:
- Right angle at B → so AC is hypotenuse = 50
- Angle C is at vertex C
- Side opposite to angle C is AB = 14
- So, sin C = opposite/hypotenuse = 14/50 = 7/25 = 0.28
✔ Check: 14 ÷ 50 = 0.28 — correct.
---
Problem 2: sin Z in triangle XYZ (right angle at X)
Triangle XYZ:
- Right angle at X → so YZ is hypotenuse = 40
- Angle Z is at vertex Z
- Side opposite to angle Z is XY = 24
- So, sin Z = opposite/hypotenuse = 24/40 = 3/5 = 0.6
✔ Check: 24 ÷ 40 = 0.6 — correct.
---
Problem 3: tan A in triangle ABC (right angle at B)
Triangle ABC:
- Right angle at B → so AC is hypotenuse? Wait — actually, sides are labeled: CA=29, CB=21, BA=20, right angle at B.
→ So legs are AB = 20 and BC = 21; hypotenuse is AC = 29.
Angle A is at vertex A.
Opposite to angle A is BC = 21
Adjacent to angle A is AB = 20
So tan A = opposite/adjacent = 21/20 = 1.05
✔ Check: 21 ÷ 20 = 1.05 — correct.
---
Problem 4: tan B in triangle ABC (right angle at A)
Triangle ABC:
- Right angle at A → so BC is hypotenuse = 50
Legs: AB = 40, AC = 30
Angle B is at vertex B.
Opposite to angle B is AC = 30
Adjacent to angle B is AB = 40
So tan B = opposite/adjacent = 30/40 = 3/4 = 0.75
✔ Check: 30 ÷ 40 = 0.75 — correct.
---
Problem 5: cos X in triangle XYZ (right angle at Y)
Triangle XYZ:
- Right angle at Y → so XZ is hypotenuse = 29
Legs: XY = 21, YZ = 20
Angle X is at vertex X.
Adjacent to angle X is XY = 21
Hypotenuse is XZ = 29
So cos X = adjacent/hypotenuse = 21/29 ≈ ?
Let’s calculate: 21 ÷ 29 = 0.724137... → but we don’t need decimal yet unless asked. The question doesn’t specify format, but since others are fractions or decimals, let’s leave as fraction unless calculator needed later. But wait — problems 7 and 8 say “use calculator”, so maybe these first six can be exact fractions.
But looking back: Problem 5 says “cos X = ___” — no instruction to round, so we can write exact value.
21/29 is already simplified.
But let me check if they want decimal? No — only 7 and 8 say “use calculator”. So for 1–6, exact values are fine.
Wait — problem 6 also doesn’t say calculator. So we’ll keep fractions where possible.
But let’s see what’s expected. In problem 1, 14/50 reduces to 7/25. Similarly here, 21/29 is simplest form.
Actually, let’s double-check labeling:
Triangle XYZ: right angle at Y → points X, Y, Z.
Side XY = 21, YZ = 20, XZ = 29.
Angle X: between sides XY and XZ.
Adjacent to angle X: XY = 21
Opposite: YZ = 20
Hypotenuse: XZ = 29
Yes, cos X = adjacent/hypotenuse = 21/29
✔ Correct.
---
Problem 6: cos C in triangle ABC (right angle at B)
Triangle ABC:
- Right angle at B → so AC is hypotenuse = 15
Legs: AB = 9, BC = 12
Angle C is at vertex C.
Adjacent to angle C is BC = 12
Hypotenuse is AC = 15
So cos C = adjacent/hypotenuse = 12/15 = 4/5 = 0.8
✔ Check: 12 ÷ 15 = 0.8 — correct.
---
Now Problems 7 and 8 require calculator, rounded to nearest ten-thousandth (4 decimal places).
Problem 7: sin 77°
Using calculator: sin(77) ≈ 0.974370064...
Rounded to 4 decimal places: look at fifth digit → 7, so round up fourth digit from 3 to 4? Wait:
0.97437 → digits after decimal: 9 (tenths), 7 (hundredths), 4 (thousandths), 3 (ten-thousandths), 7 (hundred-thousandths)
So ten-thousandths place is the 4th decimal: currently 3, next digit is 7 ≥ 5 → round up → 0.9744
✔ sin 77° ≈ 0.9744
---
Problem 8: tan 17°
Calculator: tan(17) ≈ 0.305730681...
Digits: 0.30573...
Ten-thousandths place is 4th decimal: 7, next digit is 3 < 5 → do not round up.
So tan 17° ≈ 0.3057
✔ Confirmed.
---
Final Answers:
1. sin C = 14/50 = 7/25 → but usually written as decimal or reduced fraction. Since 14/50 reduces to 7/25, and 7/25 = 0.28, either is acceptable. But in context, probably decimal or simplified fraction. Looking at other answers, some are decimals. Let's go with simplified fraction unless specified.
Wait — problem 1: 14/50 simplifies to 7/25. But 7/25 is 0.28 exactly. Either is fine. I'll write as fraction unless decimal is clearer.
But in school worksheets, often they accept both. However, since problem 6 gives 12/15 which reduces to 4/5, likely they expect simplified fractions.
But let’s check problem 2: 24/40 = 3/5 = 0.6 — again, same.
To be safe, I’ll provide simplified fractions for 1–6, and decimals for 7–8 as instructed.
But problem 3: 21/20 is improper fraction — that’s okay.
Alternatively, maybe they want decimals for all? But 7 and 8 specifically say “use calculator”, implying others may not need it.
Looking at the worksheet layout, blanks are just lines — no specification. But in math class, for exact values, fractions are preferred.
However, let’s see: in problem 1, 14/50 = 0.28 exactly — so decimal is fine.
I think for consistency, since 7 and 8 require decimals, and others can be exact, I’ll write exact values (fractions or whole numbers) for 1–6, and decimals for 7–8.
But let me verify standard practice: in trig ratios, if it’s a nice decimal, sometimes they write decimal. But 21/29 is not nice, so fraction is better.
Actually, re-examining: problem 5 is 21/29 — that’s approximately 0.7241, but since no calculator instruction, leave as fraction.
Similarly, problem 3: 21/20 = 1.05 — that’s exact decimal.
Hmm. To avoid confusion, I’ll present all answers in the most appropriate form:
- If it simplifies to a terminating decimal, use decimal.
- Otherwise, use fraction.
- For 7 and 8, use decimal as instructed.
So:
1. sin C = 14/50 = 0.28 → 0.28 (since it terminates)
2. sin Z = 24/40 = 0.6 → 0.6
3. tan A = 21/20 = 1.05 → 1.05
4. tan B = 30/40 = 0.75 → 0.75
5. cos X = 21/29 → this does not terminate, so 21/29 (but wait, is that acceptable? Maybe they expect decimal? But no calculator instruction. I think fraction is fine.)
- However, looking at the worksheet, all blanks are equal size, and 21/29 might be messy. Perhaps I should compute it? But instructions say only 7 and 8 use calculator.
- Actually, let me check: in many textbooks, for such problems, if it’s not a nice number, they leave as fraction. But 21/29 is about 0.7241, but without calculator, student might not know.
- Wait — perhaps I made a mistake? Is there a way it simplifies? 21 and 29 share no common factors (29 is prime), so 21/29 is simplest.
But let’s see problem 6: 12/15 = 0.8 — nice decimal.
Perhaps for consistency, since 1-4 and 6 give nice decimals, and 5 does not, but the problem doesn't specify, I'll write 21/29 for problem 5.
However, upon second thought, in the context of "finding trigonometric ratios" with given side lengths, and no mention of calculator for 1-6, the expected answer is likely the ratio as a fraction or simplified form.
But to match the style, let's see: in problem 1, 14/50 could be left as is, but usually simplified.
I recall that in such worksheets, they often expect the ratio in simplest form, whether fraction or decimal.
For problem 5, 21/29 is already simplified, so I'll keep it as fraction.
But let's confirm with calculation: 21 divided by 29 is approximately 0.7241, but since no calculator, fraction is better.
Actually, I think I should provide the exact value as per definition.
Final decision:
- Problems 1-6: exact values (simplified fractions or decimals if terminating)
- Problems 7-8: decimals to 4 places
So:
1. sin C = 14/50 = 7/25 or 0.28 — I'll use 0.28 since it's exact and simple.
2. sin Z = 24/40 = 3/5 = 0.6
3. tan A = 21/20 = 1.05
4. tan B = 30/40 = 3/4 = 0.75
5. cos X = 21/29 — leave as fraction
6. cos C = 12/15 = 4/5 = 0.8
7. sin 77° = 0.9744
8. tan 17° = 0.3057
But for problem 5, if I write 21/29, is that acceptable? Yes.
To be thorough, let's list all:
After careful consideration, I'll present:
1. 0.28
2. 0.6
3. 1.05
4. 0.75
5. \frac{21}{29} (but since the blank is for a number, perhaps decimal? But no calculator. I think fraction is fine.)
Wait — looking back at the user's image description, it's a worksheet with blanks, and for 7 and 8, it specifies "use calculator", implying for 1-6, you can do it without, so fractions are expected for non-terminating.
But 21/29 is not nice, but it's correct.
Perhaps I can write it as a decimal approximation? But that would be inconsistent.
Another idea: maybe I miscalculated which sides are which.
In problem 5: triangle XYZ, right angle at Y.
Points: X, Y, Z.
Sides: XY = 21, YZ = 20, XZ = 29.
Angle at X: so from X, the sides are to Y and to Z.
The side adjacent to angle X is XY = 21 (since it's next to X and not the hypotenuse).
The hypotenuse is XZ = 29.
Yes, cos X = adjacent/hypotenuse = 21/29.
Correct.
I think it's fine.
For the final answer, I'll write:
1. 0.28
2. 0.6
3. 1.05
4. 0.75
5. \frac{21}{29}
6. 0.8
7. 0.9744
8. 0.3057
But since the output should be plain text, for problem 5, I'll write "21/29".
Similarly, others as decimals or fractions.
To make it uniform, perhaps convert all to decimals where possible, but for 5, it's irrational? No, it's rational but repeating? 21/29 = 0.724137931... repeating, so not terminating.
So best to leave as fraction.
Final Answer:
1. 0.28
2. 0.6
3. 1.05
4. 0.75
5. 21/29
6. 0.8
7. 0.9744
8. 0.3057
But let's write them in order as per the problems.
──────────────────────────────────────
Final Answer:
1. 0.28
2. 0.6
3. 1.05
4. 0.75
5. 21/29
6. 0.8
7. 0.9744
8. 0.3057
Parent Tip: Review the logic above to help your child master the concept of trig ratios worksheet pdf.