This Grade 4 worksheet mixes side lengths and angle measures to classify triangles two ways. Students fill in blanks about equilateral, isosceles, and scalene triangles, then match angle sets to combined names. The matching set links angles like 90, 45, 45 to right isosceles, helping students describe each triangle fully and confidently. This Grade 4 worksheet supports classroom practice and homework review at home.
Style:
Classifying Triangles
Part A: Fill in the Blank
Write the missing word or number on each line.
1. A triangle with sides of 5 cm, 5 cm, and 5 cm is called an equilateral triangle.
2. A triangle with sides of 7 in, 7 in, and 4 in is called an isosceles triangle.
3. A triangle with sides of 3 cm, 4 cm, and 5 cm is called a scalene triangle.
4. If a triangle has angles of 80, 60, and 40 degrees, the missing angle keeps the total at 180.
5. A right triangle always has exactly one angle that measures 90 degrees.
6. A triangle with angles 110, 35, and 35 degrees is an obtuse isosceles triangle.
7. A triangle that is both right and isosceles has angles 90, 45, and 45 degrees.
8. Angles 60, 60, 60 describe an equilateral triangle, which is also an acute triangle by angle.
9. A triangle with angles of 95, 45, and 40 degrees is an obtuse triangle.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Angles 60, 60, 60
→ Equilateral acute
Acute scalene
Angles 90, 45, 45
→ Right isosceles
Right isosceles
Angles 100, 40, 40
→ Obtuse isosceles
Equilateral acute
Angles 80, 60, 40
→ Acute scalene
Obtuse isosceles
Classifying Triangles
★ Part A: Fill in the Blank
Write the missing word or number on each line.
1) A triangle with sides of 5 cm, 5 cm, and 5 cm is called an equilateral triangle.
2) A triangle with sides of 7 in, 7 in, and 4 in is called an isosceles triangle.
3) A triangle with sides of 3 cm, 4 cm, and 5 cm is called a scalene triangle.
4) If a triangle has angles of 80, 60, and 40 degrees, the missing angle keeps the total at 180.
5) A right triangle always has exactly one angle that measures 90 degrees.
6) A triangle with angles 110, 35, and 35 degrees is an obtuse isosceles triangle.
7) A triangle that is both right and isosceles has angles 90, 45, and 45 degrees.
8) Angles 60, 60, 60 describe an equilateral triangle, which is also an acute triangle by angle.
9) A triangle with angles of 95, 45, and 40 degrees is an obtuse triangle.
★ Part B: Matching
Match each item on the left to the correct answer on the right.
1) Match each item to its correct answer.
Angles 60, 60, 60
→ Equilateral acute
Acute scalene
Angles 90, 45, 45
→ Right isosceles
Right isosceles
Angles 100, 40, 40
→ Obtuse isosceles
Equilateral acute
Angles 80, 60, 40
→ Acute scalene
Obtuse isosceles
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10 Questions
10-15 minutes
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