Question

Use the law of cosines to find each missing side. Round to the nearest tenth

Answer 1

The law of cosine helps us to know the third side of a triangle when two sides of the triangle are already known. The value of x is 117.8°. thus, the correct option is A.

What is the Law of Cosine?

The law of cosine helps us to know the third side of a triangle when two sides of the triangle are already known the angle opposite to the third side is given. It is given by the formula,

$Cos(\theta) = \dfrac{a^2+b^2-c^2}{2ab}$

where

c is the third side of the triangle

a and b are the other two sides of the triangle,

and θ is the angle opposite to the third side, therefore, opposite to side c.

As per the law of cosine, the measure of angle x can be written as,

$Cos(x) = \dfrac{12^2+5^2-15^2}{2(5)(12)}\\\\Cos(x) = \dfrac{-56}{120}\\\\x = 117.8^o$

Hence, the value of x is 117.8°. thus, the correct option is A.

Learn more about the Law of Cosine:

brainly.com/question/17289163

#SPJ1