Finding the Missing Angles

Front

What is an angle?

Back

An angle is formed by two rays (sides) that share a common endpoint (vertex). It is measured in degrees.

Front

What is the sum of angles in a triangle?

Back

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

Front

What is a right angle?

Back

A right angle measures exactly 90°.

Front

What is an acute angle?

Back

An acute angle is an angle that measures less than 90°.

Front

What is an obtuse angle?

Back

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

Front

How do you find a missing angle in a triangle?

Back

To find a missing angle in a triangle, subtract the sum of the known angles from 180°.

Front

What is a straight angle?

Back

A straight angle measures exactly 180°.

Front

What is a complementary angle?

Back

Complementary angles are two angles whose measures add up to 90°.

Front

What is a supplementary angle?

Back

Supplementary angles are two angles whose measures add up to 180°.

Front

If one angle measures 30°, what is its complementary angle?

Back

The complementary angle is 60° (90° - 30°).