Answer : 118 or -40
Explanation I didn’t know which one you meant
1. Which polygon or polygons are regular?
A regular polygon is a polygon that is equiangular (all angles are equal in measure) and equilateral (all sides have the same length).
Therefore your answer is:
A. equilateral triangle
C. square
2. Which polygon is always irregular?
traingle - NOT (equilateral triangle)
trapezoid - YES
square - NOT
hexagon - NOT (regular hexagon)
Vertical angles are equal
5x - 40 = 3x + 8
5x - 3x = 8 + 40
2x = 48
x = 48/2
x = 24
m∠ABC = 3x + 8 = 3 * 24 + 8 = 80°
(or m∠ABC = 5x - 40 = 5 * 24 - 40 = 80°)