Angle Relationships

Front

What is an angle?

Back

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

Front

What is a right angle?

Back

A right angle is an angle that measures exactly 90 degrees.

Front

What is an acute angle?

Back

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

Front

What is an obtuse angle?

Back

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

Front

What is a straight angle?

Back

A straight angle is an angle that measures exactly 180 degrees.

Front

What are complementary angles?

Back

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

Front

What are supplementary angles?

Back

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

Front

What are vertical angles?

Back

Vertical angles are the angles opposite each other when two lines intersect. They are always equal.

Front

How do you find the missing angle in a triangle?

Back

The sum of the angles in a triangle is always 180 degrees. Subtract the sum of the known angles from 180 to find the missing angle.

Front

If one angle is 70 degrees, what is the measure of its complementary angle?

Back

The complementary angle is 20 degrees (90 - 70 = 20).