# Angles of a Parallelogram

How to solve the angles of a parallelogram problems: properties, example, and its solution.

## Properties

There are two properties

related to the angles of a parallelogram.

The opposite interior angles are congruent.

(same colored angles)

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.

## Example

∠*A* and ∠*D* are consecutive interior angles

in the parallelogram.

So m∠*A* + 70 = 180.

m∠*A* = 110.

∠*B* and ∠*D* are opposite interior angles

in the parallelogram.

So m∠*B* = m∠*D* = 70.

∠*A* and ∠*C* are opposite interior angles

in the parallelogram.

So m∠*C* = m∠*A* = 110.