Answer:
The base angles measure 78.46 degrees to the nearest hundredth.
Step-by-step 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
