Finding Unknown Angles

Front

What is an angle?

Back

An angle is formed by two rays (sides) that meet at a common endpoint called the vertex.

Front

What is a right angle?

Back

A right angle measures exactly 90 degrees.

Front

What is an acute angle?

Back

An acute angle measures less than 90 degrees.

Front

What is an obtuse angle?

Back

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

Front

What do we call angles that add up to 90 degrees?

Back

Complementary angles.

Front

What do we call angles that add up to 180 degrees?

Back

Supplementary angles.

Front

If two angles are complementary and one angle measures 30 degrees, what is the measure of the other angle?

Back

60 degrees.

Front

If two angles are supplementary and one angle measures 120 degrees, what is the measure of the other angle?

Back

60 degrees.

Front

What is the measure of a straight angle?

Back

A straight angle measures exactly 180 degrees.

Front

What is the sum of angles in a triangle?

Back

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