Question

Use the Law of Cosines to find the missing angle.
Find m∠B, given a = 11, b = 12, and c = 17.

Answer 1

If this is a regular triangle and not a right triangle, the answer would be approximately 44.66 degrees. 

Answer 2

The measure of angle B is 44.66°.

Explanation:

Given information: a = 11, b = 12, and c = 17

According to the law of cosine

`\cos B=(a^2+c^2-b^2)/(2ac)`

Where, a, b and c are sides of the triangle.

`\cos B=((11)^2+(17)^2-(12)^2)/(2(11)(17))`

`\cos B=(121+289-144)/(374)`

`\cos B=(266)/(374)`

`\cos B=0.711229946524`

`B=\cos^(-1) 0.711229946524`

`B=44.6649245311^(\circ)`

`B\approx 44.66^(\circ)`

Therefore, the measure of angle B is 44.66°.