3.2 Interior and Exterior Angles of Triangles

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 an exterior angle of a triangle?

Back

An exterior angle of a triangle is formed by one side of the triangle and the extension of an adjacent side.

Front

What is the relationship between an exterior angle and the interior angles of a triangle?

Back

An exterior angle is equal to the sum of the two opposite interior angles.

Front

What are acute angles?

Back

Angles that measure less than 90 degrees are called acute angles.

Front

What are obtuse angles?

Back

Angles that measure more than 90 degrees but less than 180 degrees are called obtuse angles.

Front

What is a right angle?

Back

An angle that measures exactly 90 degrees is called a right angle.

Front

What is a scalene triangle?

Back

A scalene triangle is a triangle with all sides of different lengths.

Front

What is an isosceles triangle?

Back

An isosceles triangle has at least two sides that are equal in length and two angles that are equal.

Front

What is an equilateral triangle?

Back

An equilateral triangle has all three sides of equal length and all three angles measuring 60 degrees.

Front

How do you find the measure of an unknown angle in a triangle?

Back

Subtract the sum of the known angles from 180 degrees.