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Grade 8 Math: Exterior Angle Property

A worksheet for 8th-grade students to practice understanding and applying the exterior angle property of triangles.

Grade 8 Math GeometryExterior Angle Property
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Includes

3 Short AnswerMultiple ChoiceFill in the BlanksTrue / False

Standards

CCSS.MATH.CONTENT.8.G.A.5

Topics

mathgeometryexterior angletrianglegrade 8
8 sections · Free to use · Printable
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Grade 8 Math: Exterior Angle Property

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Read each question carefully and use the exterior angle property of triangles to find the unknown angles or solve the problems. Show all your work.

1. In your own words, explain the Exterior Angle Property of a triangle.

2. An exterior angle of a triangle is equal to:

a

The sum of the adjacent interior angles.

b

The sum of the two opposite interior angles.

c

180 degrees minus the adjacent interior angle.

d

The sum of all three interior angles.

3. Find the value of x in the diagram below.

x60°70°

4. If an exterior angle of a triangle is 110° and one of the interior opposite angles is 45°, what is the measure of the other interior opposite angle?

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

6. A linear pair consists of an interior angle and its   exterior angle, and their sum is always   degrees.

7. The exterior angle of a triangle is always greater than either of its interior opposite angles.

T

True

F

False

8. The sum of an exterior angle and its adjacent interior angle is 90 degrees.

T

True

F

False

9. In a triangle ABC, the exterior angle at C is 130°. If angle A is 60°, find the measure of angle B.