This Grade 4 worksheet asks students to classify triangles two ways, by sides and by angles. Learners decide whether each triangle is equilateral, isosceles, or scalene and also acute, right, or obtuse. Fill in the blank items combine both classifications, and a matching activity links triangle descriptions to their full names, building flexible understanding of how side and angle properties work together to fully describe a triangle.
Style:
Classifying Triangles
Part A: Fill in the Blank
Write the missing word or number on each line.
1. A triangle with three congruent sides and three 60 degree angles is equilateral and acute.
2. A triangle with two congruent sides and a 90 degree angle is isosceles and right.
3. A triangle with three different side lengths and one 110 degree angle is scalene and obtuse.
4. A triangle with sides 4, 4, 4 and angles 60, 60, 60 can be classified as equilateral and acute.
5. A triangle with two equal sides and a 100 degree vertex angle is isosceles and obtuse.
6. A triangle with three different sides and three angles of 50, 60, and 70 is scalene and acute.
7. A triangle with two congruent sides and three angles of 70, 70, and 40 is isosceles and acute.
8. A triangle with three different sides and a 90 degree angle is scalene and right.
9. A triangle with sides 6, 6, 8 and angles 70, 70, 40 is isosceles and acute.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Equilateral with all 60 degree angles
→ Equilateral and acute
Equilateral and acute
Isosceles with a 90 degree angle
→ Isosceles and right
Isosceles and right
Scalene with a 120 degree angle
→ Scalene and obtuse
Scalene and obtuse
Scalene with angles 50, 60, 70
→ Scalene and acute
Scalene and acute
Classifying Triangles
★ Part A: Fill in the Blank
Write the missing word or number on each line.
1) A triangle with three congruent sides and three 60 degree angles is equilateral and acute.
2) A triangle with two congruent sides and a 90 degree angle is isosceles and right.
3) A triangle with three different side lengths and one 110 degree angle is scalene and obtuse.
4) A triangle with sides 4, 4, 4 and angles 60, 60, 60 can be classified as equilateral and acute.
5) A triangle with two equal sides and a 100 degree vertex angle is isosceles and obtuse.
6) A triangle with three different sides and three angles of 50, 60, and 70 is scalene and acute.
7) A triangle with two congruent sides and three angles of 70, 70, and 40 is isosceles and acute.
8) A triangle with three different sides and a 90 degree angle is scalene and right.
9) A triangle with sides 6, 6, 8 and angles 70, 70, 40 is isosceles and acute.
★ Part B: Matching
Match each item on the left to the correct answer on the right.
1) Match each item to its correct answer.
Equilateral with all 60 degree angles
→ Equilateral and acute
Equilateral and acute
Isosceles with a 90 degree angle
→ Isosceles and right
Isosceles and right
Scalene with a 120 degree angle
→ Scalene and obtuse
Scalene and obtuse
Scalene with angles 50, 60, 70
→ Scalene and acute
Scalene and acute
Ready to Practice?
Complete each section carefully.
10 Questions
10-15 minutes
Auto-graded
Retry anytime
🏆
Questions Correct
0
Correct
0
Incorrect
0
Skipped
0:00
Time
0%
Score
Review Your Answers
See what you got right, missed, or skipped.