Question

Use the law of cosines to find the value of cos. (see pic attached inside!!) Round the answer to two decimal places!

A. 0.84

B. 0.35

C. 0.23

D. 1.23

Answer 1

The CORRECT anser is 0.22

Explanation:

I took the test and I got stumped, so I checked here and the answer that was provided was WRONG!!!

Answer 2

Option A) 0.84

Explanation:

Given is a triangle with sides 10.2, 9.8 and 5.7

We are to find the angle opposite the side 5.7

We can use cosine law for triangles

`5.7^2=10.2^2+9.8^2-2(10.2)(9.8) cos\theta`

Simplify to get

`32.49=104.04+96.04-199.92cos\theta`

Simplify to get

`cos \theta =08382`

Round off to get 0.84

Hence option A is right answer