Exterior Angle Theorem and Triangle Congruence

The measure of an exterior angle of a triangle is equal to the sum of the measures of its remote interior angles.
m∠4 = m∠1 + m∠2

• Triangle Sum Theorem

• Exterior Angle Theorem

• Third Angles Theorem

• Congruent Triangles Theorem

Find the measure of the indicated angle. 

• 95°

• 85°

• 35°

• 45°

Solve for x

• 30°

• 40°

• 50°

• 60°

Use the Exterior Angle Theorem to find the value of x.

• 1.5

• 4.3

• 7

In the triangle shown, ∠ BAC (angle A) = 5y + 3 and ∠ ABC (angle B) = 4y + 8 , and the measure of the exterior angle ∠ HMN is 146º. What is the value of y?

• 15

• 5

• 19

• 2.5

Find the measure of the indicated angle. 

• 34°

• 46°

• 62°

• 36°

What is Statement?

• ∠MNL ≌ ∠ONP

• MN ≌ ON

• N ≌ N

• MO ≌ OM

Can the triangles be proven congruent?  If so, how?

• ASA

• AAS

• SAS

• Cannot be proven congruent

Which theorem can be used to justify that \angle1+\angle2=\angle4?

• Triangle Sum Theorem

• Alternate Interior Angles Postulate

• Vertical Angles Postulate

• Exterior Angles Theorem

Which is true by the Exterior Angle Theorem?