Angle Relationships

Front

What is an acute angle?

Back

An angle that measures less than 90°.

Front

What is an obtuse angle?

Back

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

Front

What is a right angle?

Back

An angle that measures exactly 90°.

Front

What is a straight angle?

Back

An angle that measures exactly 180°.

Front

What is the sum of angles in a triangle?

Back

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

Front

If one angle in a triangle is 90°, what type of triangle is it?

Back

It is a right triangle.

Front

What do you call two angles that add up to 90°?

Back

Complementary angles.

Front

What do you call two angles that add up to 180°?

Back

Supplementary angles.

Front

What is the measure of an angle that is complementary to a 30° angle?

Back

60°.

Front

What is the measure of an angle that is supplementary to a 120° angle?

Back

60°.