Question

#1 Using the right triangle below, find the cosine of angle A.

Answer 1

Answer: 0.8

Explanation:

Using the Cosine formula :

`Cos A = (b^(2)+c^(2)-a^(2))/(2bc)`

`a = 6`

`b = 8`

`c = 10`

substituting into the formula , we have

`Cos A = (8^(2)+10^(2)-6^(2))/(2(8)(10))`

`Cos A = (64+100-36)/(160)`

`Cos A = (164-36)/(160)`

`Cos A = (128)/(160)`

Therefore :

Cosine of angle A = 0.8