Question

Whats his mistake and the correct awnser

Answer 1

θ ≈ 35.7°

Explanation:

His mistake was in using the wrong trig. ratio

Instead of using cosine he should have used the sine ratio

sinθ =
`(opposite)/(hypotenuse)` =
`(7)/(12)` , then

θ =
`sin^(-1)` (
`(7)/(12)` ) ≈ 35.7° ( to the nearest tenth )