Geometry Terminology

Front

What is the definition of 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 difference between acute, right, and obtuse angles?

Back

An acute angle is less than 90 degrees, a right angle is exactly 90 degrees, and an obtuse angle is greater than 90 degrees but less than 180 degrees.

Front

What is the definition of complementary angles?

Back

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

Front

What is the definition of supplementary angles?

Back

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

Front

What are vertical angles?

Back

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

Front

What are adjacent angles?

Back

Adjacent angles are two angles that share a common side and a common vertex but do not overlap.

Front

How do you name an angle using three points?

Back

To name an angle using three points, the vertex point is always the middle point. For example, angle ABC is formed by points A and C with B as the vertex.

Front

What is the relationship between angle ABC and angle CBD if they share a common side?

Back

If angle ABC and angle CBD share a common side, they are considered adjacent angles.

Front

What is the formula to find the measure of an angle in a triangle?

Back

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

Front

What is the definition of a right triangle?

Back

A right triangle is a triangle that has one angle measuring exactly 90 degrees.