Exterior Angle Theorem

Front

What is the Exterior Angle Theorem?

Back

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

Front

If an exterior angle measures 42°, what is the sum of the two opposite interior angles?

Back

The sum of the two opposite interior angles is 42°.

Front

Set up an equation to find x: 42 + 8x = ?

Back

2 + 12x.

Front

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

Back

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

Front

If m∠A = 42° and m∠B = 67°, what is m∠C if C is the exterior angle at vertex A?

Back

m∠C = m∠A + m∠B = 42° + 67° = 109°.

Front

Find m∠B if m∠A = 42° and m∠C = 67° in a triangle.

Back

m∠B = 180° - (m∠A + m∠C) = 180° - (42° + 67°) = 71°.

Front

Solve for x in the equation: 42 + 8x = 2 + 12x.

Back

x = 4.

Front

What is the measure of x if the equation is 42 + 8x = 180?

Back

x = 17.25.

Front

If m∠A = 101° and m∠B = 111°, what is the measure of the exterior angle at vertex A?

Back

The exterior angle at vertex A = m∠B + m∠C.

Front

What is the measure of an exterior angle if the two opposite interior angles are 54° and 67°?

Back

The exterior angle = 54° + 67° = 121°.