Answer:
C) 103°
Step-by-step explanation:
Because this is an isosceles trapezoid, it will have 2 pairs of equal angles. If angle YES is equal to 77°, that means that the angle that is on the same side as it will also equal 77°. Angles YRS and ERS are also equal. Assume that angle equals x. Knowing this, you can use the equation:
77+77+2x = 360
154+2x = 360
2x =360-154=206
x=206/2
x=103°
