# Solve the triangle. B = 73°, b = 15, c = 8, find the remaining side.

Two important laws to find the missing side or angle of a triangle are Sine and Cosine rule.

## Answer: The value of the unknown side of the triangle is 15.22 units

Go through the solution to understand better.

**Explanation**:

Given, B = 73°, b = 15, c = 8

Applying the cosine rule:

b^{2} = a^{2} + c^{2} - 2ac cos B

(15)^{2} = (a)^{2 }+ (8)^{2 }- 2a(8) cos 73º

225 = a^{2} + 64 -16a × 0.29

0 = a^{2} - 4.64a - 161

On solving the quadratic using Cuemaths quadratic calculator, we get:

a = 15.22