Answer:
A
Step-by-step explanation:
The sum of the 3 angles in a triangle = 180°
let x be the measure of the congruent angles, then
x + x + 100 = 180, that is
2x + 100 = 180 ( subtract 100 from both sides )
2x = 80 ( divide both sides by 2 )
x = 40
Thus the measure of one of the congruent angles is 40°
