Question

A triangle has sides A, B, and C. Sides A and B are of lengths `8` and `1`, respectively, and the angle between A and B is `pi/12`. What is the length of side C?

Answer 1

≈ 7.039

Explanation:

Given 2 sides and the angle between them , as in this question use the `color(blue) " Cosine rule "`

For this triangle this is `C^2 = A^2 + B^2 - (2ABcos(pi/12))`

hence:`C^2 = 8^2 + 1^2 - (2xx8xx1 cos(pi/12))`

`= 64 + 1 -( 16 cos(pi/12)) ≈ 49.545`

`rArr C^2 = 49.545 rArr C = sqrt49.545 ≈ 7.039`