Types of Triangles Practice Questions

Review the following concept if necessary: Types of Triangles Study Guide.

Types of Triangles Practice Questions

Problems

Classify each triangle shown or described as equilateral, isosceles, or scalene.

1. 
2. 
3. 
4. 
5. 
6. ΔABC with AB = 10, BC = 10, and AC = 8.
7. ΔDEF with DE = 6, EF = 8, and DF = 10.
8. ΔXYZ with XY = 7, YZ = 7, and XZ = 7.

Name the legs, vertex angle, base angles, and base of the isosceles triangles.

Classify each triangle shown or described as acute, right, obtuse, or equiangular.

12. 
13. 
14. 
15. 
16. ΔMNO with mM= 130°, mN = 30°, and mO = 20°.
17. ΔRST with mR = 80°, mS = 45°, and mT = 55°.
18. ΔGHI with mG = 20°, mH = 70°, and mI = 90°.

Determine whether the following statements are true or false.

19. The vertex angle of an isosceles triangle will always be the smallest angle.
20. An equilateral triangle is also an equiangular triangle.
21. An isosceles triangle may also be a right triangle.
22. It is possible for a scalene triangle to be equiangular.
23. It is possible for a right triangle to be equilateral.
24. It is possible for an obtuse triangle to be isosceles.
25. An equilateral triangle is also an acute triangle.
26. A triangle can have two obtuse angles.
27. A triangle cannot have more than one right angle.

Give the answer to each question based on the readings from the lesson.

28. The non-congruent side of an isosceles triangle is called the _____.
29. List the types of triangles with at least two acute angles.
30. A small curve made on an angle of a triangle signifies _____.

Answers

1. equilateral
2. isosceles
3. scalene
4. scalene
5. scalene
6. isosceles
7. scalene
8. equilateral
9. legs: and

vertex angle: Y

base angles: X and Z

base:

10. legs: and

vertex angle: S

base angles: R and T

base:

11. legs: and

vertex angle: E

base angles: D and F

base:

12. acute
13. equiangular and acute
14. right
15. obtuse
16. obtuse
17. acute
18. right
19. false
20. true
21. true
22. false
23. false
24. true
25. true
26. false
27. true
28. base
29. acute, equiangular, right, obtuse, isosceles, equilateral, and scalene
30. a congruent angle