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Exterior Angle of a Triangle Worksheet

Explore the properties of exterior angles of triangles with this Grade 10 math worksheet, including calculations and problem-solving.

Grade 10 Math GeometryExterior Angle of a Triangle
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2 Short AnswerMultiple ChoiceFill in the BlanksCustom

Standards

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

Topics

GeometryTrianglesExterior AngleGrade 10
7 sections · Free to use · Printable
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Exterior Angle of a Triangle

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Read each question carefully and answer to the best of your ability. Show all work where necessary.

1. What is the relationship between an exterior angle of a triangle and its two opposite interior angles?

2. In triangle ABC, if the exterior angle at vertex C is 120 degrees, and angle A is 50 degrees, what is the measure of angle B?

a

60 degrees

b

70 degrees

c

120 degrees

d

130 degrees

3. The sum of the interior angles of a triangle is always   degrees.

4. An exterior angle and its adjacent interior angle are   angles, meaning they add up to   degrees.

5. In the triangle below, find the value of x.

70°50°x

6. A triangle has interior angles measuring (2x + 10)°, (3x - 5)°, and (x + 20)°. Find the measure of the exterior angle adjacent to the angle (x + 20)°.