Angles, Triangles, and Algebra

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 degrees.

Front

What is an acute angle?

Back

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

Front

What is a right angle?

Back

A right angle is an angle that measures exactly 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 complementary angle?

Back

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

Front

What is a supplementary angle?

Back

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

Front

What is a vertical angle?

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

To find the missing angle in a triangle, subtract the sum of the known angles from 180 degrees.

Front

What is the formula for the sum of angles in a triangle?

Back

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