Exterior Angle Theorem Worksheet - Grade 11 Math

This worksheet focuses on applying the Exterior Angle Theorem to solve for unknown angles in triangles, suitable for Grade 11 geometry students.

Grade 11 Math GeometryExterior Angle Theorem

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Includes

2 Short AnswerFill in the BlanksMultiple ChoiceTrue / False

Standards

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

Topics

GeometryExterior Angle TheoremTrianglesAnglesGrade 11 Math

7 sections · Free to use · Printable

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Exterior Angle Theorem

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

1. In triangle ABC, if the measure of angle A is 50 degrees and the measure of angle B is 70 degrees, what is the measure of the exterior angle at vertex C?

2. An exterior angle of a triangle measures 120 degrees. One of the non-adjacent interior angles is 65 degrees. What is the measure of the other non-adjacent interior angle?

3. The Exterior Angle Theorem states that 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 acute, then the triangle must be a triangle.

5. In the given triangle, what is the value of x?

80°

100°

120°

140°

6. The exterior angle of a triangle is always greater than either of its non-adjacent interior angles.

True

False

7. Consider a triangle with interior angles (2x + 10)°, (3x - 5)°, and (x + 25)°. Find the measure of the exterior angle adjacent to the angle (x + 25)°.