The law of cosines is used to determine the third side of a triangle
The length of the missing side is 9.3
How to determine the length of the missing side
The law of cosine states that:
a^2 = b^2 + c^2 - 2bc * cos(A)
From the complete question (see attachment), we have:
b = 15, c = 13 and Angle A = 38 degrees.
So, the equation becomes
a^2 = 15^2 + 13^2 - 2 * 15 * 13 * cos(38)
Evaluate the exponents
a^2 = 225 + 169 - 2 * 15 * 13 * cos(38)
Evaluate the product
a^2 = 225 + 169 - 307.3
Evaluate the sum and the difference
a^2 = 86.7
Take the square root of both sides
a = 9.3
Hence, the length of the missing side is 9.3
Read more about law of cosines at:
https://brainly.com/question/4372174
