A triangle has two angles measuring $55^\circ$ and $35^\circ$. Which statement correctly classifies this triangle?

It is acute because $55^\circ$ and $35^\circ$ are both less than $90^\circ$

It is right because the third angle is exactly $90^\circ$

It is obtuse because the third angle is greater than $90^\circ$

It cannot be classified without a diagram

Classify Triangles Practice — Grade 5 math

Lesson 1: Classify Triangles — Practice Questions

1. A triangle has angles measuring $42^\circ$, $67^\circ$, and $71^\circ$. What type of triangle is it?
- A. Acute
- B. Obtuse
- C. Right
- D. Cannot be determined
2. A triangle has two angles measuring $48^\circ$ and $52^\circ$. The third angle measures ___°.
3. A triangle has two angles measuring $20^\circ$ and $45^\circ$. What type of triangle is it?
- A. Acute
- B. Obtuse
- C. Right
- D. Cannot be determined
4. A triangle has two angles measuring $55^\circ$ and $35^\circ$. Which statement correctly classifies this triangle?
- A. It is acute because $55^\circ$ and $35^\circ$ are both less than $90^\circ$
- B. It is right because the third angle is exactly $90^\circ$
- C. It is obtuse because the third angle is greater than $90^\circ$
- D. It cannot be classified without a diagram
5. A triangle has angles measuring $38^\circ$, $57^\circ$, and $85^\circ$. This triangle is classified as a(n) ___ triangle.
6. A garden plot is a triangle with side lengths of 8 feet, 10 feet, and 13 feet. What is the classification of this triangle?
- A. Equilateral
- B. Isosceles
- C. Scalene
- D. Cannot be determined
7. A sign is shaped like a triangle with all three sides measuring 15 inches. What type of triangle is the sign?
- A. Scalene
- B. Isosceles
- C. Equilateral
- D. Acute
8. An isosceles triangle has two sides of length 11 cm. For the triangle to also be equilateral, the third side must have a length of ___ cm.
9. A triangle has side lengths of 6 meters, 10 meters, and 6 meters. How would this triangle be classified based on its sides?
- A. Scalene
- B. Isosceles
- C. Equilateral
- D. Cannot be determined
10. Which of the following statements is always true about classifying triangles by their side lengths?
- A. An isosceles triangle must also be equilateral.
- B. An equilateral triangle is also a type of isosceles triangle.
- C. A scalene triangle has at least two equal sides.
- D. An equilateral triangle has three different side lengths.