Let’s solve Example 2 step by step.
We are told:
- A kite is 60 meters above the ground → this is the
opposite side (relative to the angle of elevation).
- The string makes an angle of elevation of 42° with the ground → that’s our angle θ.
- We need to find how long the wire is → that’s the
hypotenuse (the string itself).
So we have:
- Opposite = 60 m
- Angle = 42°
- Hypotenuse = ? (let’s call it H)
Which trig ratio uses opposite and hypotenuse?
→
Sine: sin(θ) = opposite / hypotenuse
So:
sin(42°) = 60 / H
Now solve for H:
H = 60 / sin(42°)
Let’s calculate sin(42°). Using a calculator:
sin(42°) ≈ 0.6691
Then:
H ≈ 60 / 0.6691 ≈ 89.67 meters
Let me double-check that division:
60 ÷ 0.6691 = ?
Do it carefully:
0.6691 × 89 = 0.6691 × 90 - 0.6691 = 60.219 - 0.6691 = 59.5499 → too low
Try 89.7:
0.6691 × 89.7 = let’s compute:
First, 0.6691 × 90 = 60.219
Minus 0.6691 × 0.3 = 0.20073
So 60.219 - 0.20073 = 60.01827 → very close to 60!
So H ≈ 89.7 meters is accurate enough.
Actually, using more precise calculation:
sin(42°) = sin(42) ≈ 0.669130606...
60 0.669130606 ≈ 89.672...
Rounded to one decimal place:
89.7 meters
But since the problem gives numbers like “60m” and “42°”, which are whole numbers, maybe they expect rounding to nearest meter? Let’s check:
89.672… → rounds to
90 meters if rounding to nearest whole number.
Wait — let’s see what the context expects. In Example 1, they gave answer as 42°, even though calculator showed 41.8° — so they rounded to nearest degree.
Here, length — probably reasonable to give to nearest meter or one decimal.
But let’s be precise: 60 / sin(42°) = exactly?
Using calculator: 60 ÷ sin(42) = 60 ÷ 0.6691306063588582 = 89.672277...
So approximately
89.7 meters
I think 89.7 m is fine. But let’s confirm units — yes, meters.
Final Answer:
89.7
Parent Tip: Review the logic above to help your child master the concept of sohcahtoa word problems worksheet.