Triangle Sum & Exterior Angle Theorems

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 degrees.

Front

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

Back

Each angle in an equilateral triangle measures 60 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 Exterior Angle Theorem?

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 50 degrees and another is 60 degrees, what is the measure of the third angle?

Back

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

Front

Solve for x: 2x + 30 = 180.

Back

x = 75.

Front

If the exterior angle of a triangle is 120 degrees, what is the sum of the two remote interior angles?

Back

The sum of the two remote interior angles is 60 degrees (180 - 120 = 60).

Front

What is the relationship between the angles in a right triangle?

Back

In a right triangle, one angle is 90 degrees, and the sum of the other two angles is 90 degrees.

Front

Solve for x: 3x - 15 = 45.

Back

x = 20.

Front

If one angle of a triangle is 90 degrees and another is 45 degrees, what is the measure of the third angle?

Back

The third angle measures 45 degrees (180 - 90 - 45 = 45).