Triangle Sum Theorem Worksheet

Practice problems for grade 8 students on the Triangle Sum Theorem, including finding missing angles and applying the theorem to various triangle types.

Grade 8 Math GeometryTriangle Sum Theorem

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Includes

2 Short AnswerFill in the BlanksMultiple ChoiceTrue / False

Standards

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

Topics

mathgeometrytriangleanglesgrade 8

7 sections · Free to use · Printable

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Triangle Sum Theorem

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Read each question carefully and use the Triangle Sum Theorem to find the missing angle measurements. Remember that the sum of the interior angles in any triangle is always 180 degrees.

1. Find the measure of the missing angle in the triangle below.

x =

2. An isosceles triangle has two base angles that each measure 50°. What is the measure of the third angle?

3. In an equilateral triangle, all three angles are equal, and each measures degrees.

4. A right triangle has one angle that measures degrees.

5. If a triangle has angles measuring 45°, 65°, and x°, what is the value of x?

6. It is possible for a triangle to have two obtuse angles.

True

False

7. One angle of a triangle is 75°. The other two angles are in the ratio 2:3. Find the measures of the other two angles.