# Angles of a Trapezoid

How to solve the interior angles of a trapezoid problems: property, example, and its solution.

## Definition

A trapezoid is a quadrilateral

that have a pair of parallel sides.

Base: parallel sides

Legs: non-parallel sides

## Property

The sum of the measures

of the consecutive interior angles is 180.

(purple & blue angles)

This is true because those two angles are

the consecutive interior angles in parallel lines.

To use this formula,

the angles have to include the leg.

(not the base)

## Example

m∠(purple) + m∠(blue) = 180

(*x* + 40) + 60 = 180

m∠(purple dot) + m∠(blue dot) = 180

8*y* + 108 = 180