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Find the value of x and the indicated angle measures in three geometric triangles.

Triangle with angles labeled and equations to solve for x and angle measures.

Triangle with angles labeled and equations to solve for x and angle measures.

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Show Answer Key & Explanations Step-by-step solution for: Geometry Worksheet: Exterior Angles of Triangles
To solve the problems in the image, we need to use geometric properties and relationships between angles. Let's go through each problem step by step.

---

Problem 7: Find the value of \( x \)



#### Image Description:
- Triangle \( ABC \) with \( \angle BAC = 5x^\circ \) and \( \angle ABC = 3x^\circ \).
- The triangle is a right triangle with \( \angle ACB = 90^\circ \).

#### Solution:
1. In any triangle, the sum of the interior angles is \( 180^\circ \).
2. For triangle \( ABC \):
\[
\angle BAC + \angle ABC + \angle ACB = 180^\circ
\]
3. Substitute the given values:
\[
5x + 3x + 90 = 180
\]
4. Simplify:
\[
8x + 90 = 180
\]
5. Solve for \( x \):
\[
8x = 90 \implies x = \frac{90}{8} = 11.25
\]

#### Answer:
\[
\boxed{x = 11.25}
\]

---

Problem 9: Find \( m\angle ACB \)



#### Image Description:
- Same as Problem 7.
- We already know \( \angle ACB = 90^\circ \).

#### Answer:
\[
\boxed{90^\circ}
\]

---

Problem 10: Find \( m\angle A \)



#### Image Description:
- Same as Problem 7.
- \( \angle A = \angle BAC = 5x^\circ \).

#### Solution:
1. From Problem 7, we found \( x = 11.25 \).
2. Therefore:
\[
\angle A = 5x = 5 \times 11.25 = 56.25^\circ
\]

#### Answer:
\[
\boxed{56.25^\circ}
\]

---

Problem 11: Find the value of \( x \)



#### Image Description:
- Triangle \( EFG \) with \( \angle E = 90^\circ \).
- \( \angle F = (2x + 10)^\circ \).
- \( \angle G = (x + 22)^\circ \).

#### Solution:
1. In any triangle, the sum of the interior angles is \( 180^\circ \).
2. For triangle \( EFG \):
\[
\angle E + \angle F + \angle G = 180^\circ
\]
3. Substitute the given values:
\[
90 + (2x + 10) + (x + 22) = 180
\]
4. Simplify:
\[
90 + 2x + 10 + x + 22 = 180
\]
\[
3x + 122 = 180
\]
5. Solve for \( x \):
\[
3x = 58 \implies x = \frac{58}{3} \approx 19.33
\]

#### Answer:
\[
\boxed{x = \frac{58}{3}}
\]

---

Problem 12: Find \( m\angle H \)



#### Image Description:
- Same as Problem 11.
- \( \angle H = \angle G = (x + 22)^\circ \).

#### Solution:
1. From Problem 11, we found \( x = \frac{58}{3} \).
2. Therefore:
\[
\angle H = x + 22 = \frac{58}{3} + 22
\]
3. Convert 22 to a fraction with a denominator of 3:
\[
22 = \frac{66}{3}
\]
4. Add the fractions:
\[
\angle H = \frac{58}{3} + \frac{66}{3} = \frac{124}{3} \approx 41.33^\circ
\]

#### Answer:
\[
\boxed{\frac{124}{3}}
\]

---

Problem 13: Find \( m\angle EGH \)



#### Image Description:
- Same as Problem 11.
- \( \angle EGH \) is an exterior angle to triangle \( EFG \) at vertex \( G \).

#### Solution:
1. The exterior angle \( \angle EGH \) is equal to the sum of the two non-adjacent interior angles:
\[
\angle EGH = \angle E + \angle F
\]
2. Substitute the known values:
\[
\angle E = 90^\circ, \quad \angle F = 2x + 10
\]
3. From Problem 11, \( x = \frac{58}{3} \):
\[
\angle F = 2x + 10 = 2 \left( \frac{58}{3} \right) + 10 = \frac{116}{3} + 10
\]
4. Convert 10 to a fraction with a denominator of 3:
\[
10 = \frac{30}{3}
\]
5. Add the fractions:
\[
\angle F = \frac{116}{3} + \frac{30}{3} = \frac{146}{3}
\]
6. Therefore:
\[
\angle EGH = 90 + \frac{146}{3} = \frac{270}{3} + \frac{146}{3} = \frac{416}{3} \approx 138.67^\circ
\]

#### Answer:
\[
\boxed{\frac{416}{3}}
\]

---

Problem 14: Find \( m\angle EGF \)



#### Image Description:
- Same as Problem 11.
- \( \angle EGF \) is the same as \( \angle F \).

#### Solution:
1. From Problem 11, we found:
\[
\angle F = 2x + 10
\]
2. Substitute \( x = \frac{58}{3} \):
\[
\angle F = 2 \left( \frac{58}{3} \right) + 10 = \frac{116}{3} + 10
\]
3. Convert 10 to a fraction with a denominator of 3:
\[
10 = \frac{30}{3}
\]
4. Add the fractions:
\[
\angle F = \frac{116}{3} + \frac{30}{3} = \frac{146}{3}
\]

#### Answer:
\[
\boxed{\frac{146}{3}}
\]

---

Problem 15: Find the value of \( x \)



#### Image Description:
- Triangle \( LMN \) with \( \angle L = 90^\circ \).
- \( \angle M = (5x - 2)^\circ \).
- \( \angle N = (5x - 17)^\circ \).

#### Solution:
1. In any triangle, the sum of the interior angles is \( 180^\circ \).
2. For triangle \( LMN \):
\[
\angle L + \angle M + \angle N = 180^\circ
\]
3. Substitute the given values:
\[
90 + (5x - 2) + (5x - 17) = 180
\]
4. Simplify:
\[
90 + 5x - 2 + 5x - 17 = 180
\]
\[
90 + 10x - 19 = 180
\]
\[
10x + 71 = 180
\]
5. Solve for \( x \):
\[
10x = 109 \implies x = \frac{109}{10} = 10.9
\]

#### Answer:
\[
\boxed{x = 10.9}
\]

---

Problem 16: Find \( m\angle M \)



#### Image Description:
- Same as Problem 15.
- \( \angle M = (5x - 2)^\circ \).

#### Solution:
1. From Problem 15, we found \( x = 10.9 \).
2. Therefore:
\[
\angle M = 5x - 2 = 5(10.9) - 2 = 54.5 - 2 = 52.5^\circ
\]

#### Answer:
\[
\boxed{52.5^\circ}
\]

---

Problem 17: Find \( m\angle LNM \)



#### Image Description:
- Same as Problem 15.
- \( \angle LNM = \angle N = (5x - 17)^\circ \).

#### Solution:
1. From Problem 15, we found \( x = 10.9 \).
2. Therefore:
\[
\angle N = 5x - 17 = 5(10.9) - 17 = 54.5 - 17 = 37.5^\circ
\]

#### Answer:
\[
\boxed{37.5^\circ}
\]

---

Problem 18: Find \( m\angle UND \)



#### Image Description:
- Not provided in the image. Assuming it refers to an external angle or another part of the diagram not shown.

#### Answer:
\[
\boxed{\text{Not enough information}}
\]

---

Final Answers:


\[
\boxed{
\begin{aligned}
7. & \ x = 11.25 \\
9. & \ m\angle ACB = 90^\circ \\
10. & \ m\angle A = 56.25^\circ \\
11. & \ x = \frac{58}{3} \\
12. & \ m\angle H = \frac{124}{3} \\
13. & \ m\angle EGH = \frac{416}{3} \\
14. & \ m\angle EGF = \frac{146}{3} \\
15. & \ x = 10.9 \\
16. & \ m\angle M = 52.5^\circ \\
17. & \ m\angle LNM = 37.5^\circ \\
18. & \ \text{Not enough information}
\end{aligned}
}
\]
Parent Tip: Review the logic above to help your child master the concept of exterior angle of triangle worksheet.
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