Answer:
40 degrees
Step-by-step explanation:
The sum of the angles is 180.
A 100 degree angle cannot be a base angle because then
the sum of the base angles would be 200 degrees.
The 100 must be the vertex angle.
Equation:
x + x + 100 = 180
2x = 80
x = 40 degrees.
Each of the base angles is 40 degrees.
