Lines and Angles

Front

What do you call lines that cross at right angles?

Back

Perpendicular lines.

Front

What do you call lines that will never cross?

Back

Parallel lines.

Front

What do you call lines that cross but do not form right angles?

Back

Intersecting lines.

Front

What is an angle greater than 90 degrees called?

Back

Obtuse angle.

Front

What is an angle less than 90 degrees called?

Back

Acute angle.

Front

What is an angle exactly equal to 90 degrees called?

Back

Right angle.

Front

What is a straight angle?

Back

An angle that is exactly 180 degrees.

Front

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

Back

Complementary angles.

Front

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

Back

Supplementary angles.

Front

What is the term for a pair of angles that are opposite each other when two lines cross?

Back

Vertical angles.