Practice identifying, classifying, and solving problems with triangles using side lengths, angle measures, and triangle properties.
Read each problem carefully. Show your work in the space provided.
Classifying triangles and using angle relationships
Geometry - Grade 6-8
- 1
A triangle has angle measures of 40 degrees, 60 degrees, and 80 degrees. Classify the triangle by its angles.
- 2
A triangle has side lengths of 6 cm, 6 cm, and 9 cm. Classify the triangle by its sides.
- 3
Two angles of a triangle measure 35 degrees and 75 degrees. Find the measure of the third angle.
- 4
A triangle has angle measures of 90 degrees, 30 degrees, and 60 degrees. Classify the triangle by its angles and by its sides if all side lengths are different.
- 5
Can side lengths of 4 cm, 7 cm, and 12 cm form a triangle? Explain your answer.
- 6
In triangle ABC, angle A measures 50 degrees and angle B measures 65 degrees. What is the measure of angle C?
- 7
A triangle has side lengths of 8 units, 8 units, and 8 units. Classify the triangle by its sides and explain what you know about its angles.
- 8
A triangle has one angle that measures 115 degrees. What type of triangle is it by its angles?
- 9
Find the value of x in a triangle with angles measuring x degrees, 45 degrees, and 55 degrees.
- 10
A triangle has side lengths of 5 inches, 12 inches, and 13 inches. Does it appear to be a right triangle? Use the Pythagorean relationship to explain.
- 11
In the diagram, a triangle has two equal sides. The angle between the equal sides measures 40 degrees. What are the measures of the other two angles?
- 12
The exterior angle of a triangle measures 120 degrees. The two remote interior angles are labeled 45 degrees and x degrees. Find x.
- 13
Can a triangle have angle measures of 25 degrees, 65 degrees, and 100 degrees? Explain your answer.
- 14
A scalene triangle has sides labeled 7 cm, 10 cm, and 12 cm. Which angle is the largest: the angle opposite 7 cm, the angle opposite 10 cm, or the angle opposite 12 cm?
- 15
A triangle is shown with angles labeled 2x degrees, 3x degrees, and 4x degrees. Find the value of x and the measure of each angle.