Angles, Triangles & Parallel Lines

Front

What is an angle?

Back

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

Front

What is the sum of the interior angles of a triangle?

Back

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

Front

What is a right angle?

Back

A right angle is an angle that measures exactly 90 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 is an isosceles triangle?

Back

An isosceles triangle is a triangle that has at least two sides of equal length.

Front

What is a scalene triangle?

Back

A scalene triangle is a triangle in which all three sides are of different lengths.

Front

What is a parallel line?

Back

Parallel lines are lines in a plane that never meet and are always the same distance apart.

Front

What are alternate interior angles?

Back

Alternate interior angles are pairs of angles that are on opposite sides of a transversal and inside the two lines.

Front

What are vertical angles?

Back

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