Question

Calculate cos theta to two decimal places

Answer 1

B. 0.72

Explanation:

In order to find the answer we need to use the following formula:

`a^2=b^2+c^2-2bc*cos(\theta)` where:

a, b, c are the length of the sides and
`\theta` the angle, so:

`7^2=10^2+8^2-(2*10*8)*cos(\theta)`

`49=164-(160)*cos(\theta)`

`cos(\theta)=0.71875`

In conclusion,
`cos(\theta)=0.72`, so the answer is B.