Angles

Front

What is an angle?

Back

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

Front

What is the vertex of an angle?

Back

The vertex is the point where the two rays of an angle meet.

Front

What are the different types of angles?

Back

The different types of angles are acute (less than 90°), right (exactly 90°), obtuse (greater than 90° but less than 180°), and straight (exactly 180°).

Front

What is a right angle?

Back

A right angle measures exactly 90 degrees.

Front

What is an acute angle?

Back

An acute angle measures less than 90 degrees.

Front

What is an obtuse angle?

Back

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

Front

What is a straight angle?

Back

A straight angle measures exactly 180 degrees.

Front

How do you find the measure of an unknown angle when you know the other angles?

Back

You can use the fact that the sum of angles in a triangle is 180 degrees or that angles on a straight line sum to 180 degrees.

Front

If angle GEF is 15 degrees and angle DEG is a right angle, what is the measure of angle DEF?

Back

105 degrees.

Front

What is the sum of angles in a triangle?

Back

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