Triangles Sum Theorem & Exterior Angle Theorem

Front

What is the Triangle Sum Theorem?

Back

The Triangle Sum Theorem states that the sum of the interior angles of a triangle is always 180°.

Front

What is the measure of each angle in an equilateral triangle?

Back

In an equilateral triangle, each angle measures 60°.

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 does the Exterior Angle Theorem state?

Back

The Exterior Angle Theorem states that the measure of an exterior angle is equal to the sum of the measures of the two non-adjacent interior angles.

Front

If one angle of a triangle is 90°, what type of triangle is it?

Back

It is a right triangle.

Front

What are acute angles?

Back

Acute angles are angles that measure less than 90°.

Front

What are obtuse angles?

Back

Obtuse angles are angles that measure more than 90° but less than 180°.

Front

If two angles of a triangle are 50° and 60°, what is the measure of the third angle?

Back

The third angle measures 70° (180° - 50° - 60° = 70°).

Front

What is the measure of a right angle?

Back

A right angle measures exactly 90°.

Front

How do you find the missing angle in a triangle?

Back

To find the missing angle, subtract the sum of the known angles from 180°.