Angles and Triangles

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 a triangle?

Back

A triangle is a polygon with three edges and three vertices. The sum of the interior angles of a triangle is always 180°.

Front

What are congruent angles?

Back

Congruent angles are angles that have the same measure.

Front

What is the measure of a right angle?

Back

A right angle measures 90°.

Front

What is the measure of an acute angle?

Back

An acute angle measures less than 90°.

Front

What is the measure of an obtuse angle?

Back

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

Front

What is the sum of the angles in a triangle?

Back

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

Front

What is a vertical angle?

Back

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

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°.