Question

Suppose a triangle has two sides of length 3 and 4 and that the angle between these two sides is 60 degrees . What is the length of the third side of the triangle

Answer 1

√13 ≈ 3.6056

Explanation:

The Law of Cosines can be used to figure this. If the third side is "c", then it tells you ...

c² = a² + b² - 2ab·cos(C)

c² = 3² + 4² -2(3)(4)(cos(60°)) = 9 + 16 - 24(1/2) = 13

c = √13 ≈ 3.6056

The length of the third side is √13, about 3.6056.