Question

The sides of an isosceles triangle have lengths of 10, 10, and 4. Find the measures of the base angles.

Answer 1

The base angles measure 78.46 degrees to the nearest hundredth.

Explanation:

Applying the Cosine Rule:

10^2 = 10^2 + 4^2 - 2.4.10cosX where X is a base angle.

cos X = (100 - 100 - 16)/ (-80)

cos X = -16/-80

cos X = 0.2

X = 78.463 degrees