Question

Suppose a triangle has two sides of lengths 2 and 5 and that the angle between these two sides is 60 degrees. What is the length of the third side of the triangle?

Answer 1

The answer is √19

Explanation:

Answer 2

We are given two sides and an angle in between the two sides.

Recognize this?

Side-Angle-Side.

We can use the Law of Cosines to calculate the missing side.


`c^(2) = 2^2 + 5^2 - 2 * 2 * 5 * cos(60) c^2 = 4+25-20*cos(60)`


`c^2 = 4+25-20*cos(60)`


`c^2 = 19`


`c = √(19)`