Question

In the trapezoid below, find the values of a and b

Answer 1

a = 139, b = 69

Explanation:

Using a property of trapezoids.

Each lower base angle is supplementary to the upper base angle on the same side, hence

a = 180 - 41 = 139

b = 180 - 111 = 69

Answer 2

Since it’s a trapezoid, 111 + b will equal 180, as will 41 + a.

111 + b = 180 means b = 69.

41 + a = 180 means a = 139.

This happens simply because two angles that are positioned that way between parallel lines will always be supplementary. It’s also worth noting that all angles in any quadrilateral will add up to be 360 degrees.