Answer:
x = 50
Step-by-step explanation:
Since the triangle has 2 congruent sides then it is isosceles, thus the base angles are congruent, that is x and x
The sum of the angles in a triangle = 180°, thus
x + x + 80 = 180
2x + 80 = 180 ( subtract 80 from both sides )
2x = 100 ( divide both sides by 2 )
x = 50
