Grade 12 Math: Exterior Angle Theorem Worksheet

This worksheet focuses on applying the Exterior Angle Theorem to solve for unknown angles in triangles, suitable for Grade 12 Geometry students.

Grade 12 Math GeometryExterior Angle Theorem

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Includes

3 Short AnswerFill in the BlanksTrue / False

Standards

CCSS.MATH.CONTENT.HSG.CO.C.10

Topics

mathgeometryexterior angle theoremtrianglesgrade 12

7 sections · Free to use · Printable

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Grade 12 Math: Exterior Angle Theorem

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Read each question carefully and apply the Exterior Angle Theorem to find the missing angles. Show all your work.

1. State the Exterior Angle Theorem in your own words.

2. In the triangle below, if the interior opposite angles are 70° and 50°, what is the measure of the exterior angle?

3. The measure of an exterior angle of a triangle is equal to the sum of the measures of its two interior angles.

4. If an exterior angle of a triangle is 130° and one of its interior opposite angles is 65°, then the other interior opposite angle is .

5. An exterior angle of a triangle is always greater than either of its interior opposite angles.

True

False

6. In triangle ABC, line segment CD is extended from C. If ∠A = (2x + 10)°, ∠B = (3x - 20)°, and the exterior angle at D (∠ACD) is (6x - 5)°, find the value of x.