Angles

Front

What is an angle?

Back

An angle is formed by two rays (sides of the angle) that share a common endpoint (the vertex).

Front

What is a straight angle?

Back

A straight angle measures 180° and looks like a straight line.

Front

What is a right angle?

Back

A right angle measures 90° and forms a perfect corner.

Front

What is an acute angle?

Back

An acute angle measures less than 90°.

Front

What is an obtuse angle?

Back

An obtuse angle measures more than 90° but less than 180°.

Front

How do you find the measure of an angle when given a straight angle?

Back

Subtract the measure of the known angle from 180°. For example, if one angle is 60°, the other is 180° - 60° = 120°.

Front

What is the sum of angles in a straight line?

Back

The sum of angles on a straight line is always 180°.

Front

What is the sum of angles in a triangle?

Back

The sum of angles in a triangle is always 180°.

Front

What is a complementary angle?

Back

Two angles are complementary if their measures add up to 90°.

Front

What is a supplementary angle?

Back

Two angles are supplementary if their measures add up to 180°.