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Triangles by Sides is a free printable Grade 5 maths worksheet on classifying triangles, aligned to Common Core standard 5.G.B.3. It prints 5 questions with an answer key on its own sheet of paper, in 25 versions that each ask different questions, so no two pupils in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.

Set 20 of 25 · the same problems every time you open this link.

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Set 1 has all 25 in a single PDF. All 25 sets ask different questions.

Triangles by Sides

5.G.B.3

NameDate

Sort each one into the right box.

1.Sort each one into the right box.

Sort: two equal angles, sides 6, 6, 6, sides 3, 5, 7, sides 4, 4, 6

EquilateralIsoscelesScalene
2.Sort each one into the right box.

Sort: all sides 5 cm, sides 3, 5, 7, no equal sides, sides 4, 4, 6

EquilateralIsoscelesScalene
3.Sort each one into the right box.

Sort: all sides 5 cm, sides 4, 6, 9, no equal sides, all angles 60°

EquilateralIsoscelesScalene
4.Sort each one into the right box.

Sort: no equal sides, sides 5, 5, 8, sides 6, 6, 6, sides 4, 4, 6

EquilateralIsoscelesScalene
5.Sort each one into the right box.

Sort: sides 4, 6, 9, sides 3, 5, 7, all angles 60°, sides 6, 6, 6

EquilateralIsoscelesScalene

LessonPrint · 5.G.B.3 · Set 20 · free to copy for classroom use

Answer key — Triangles by Sides

Set 20. Prints on its own sheet.

  1. 1.Equilateral: sides 6, 6, 6; Isosceles: two equal angles, sides 4, 4, 6; Scalene: sides 3, 5, 7
  2. 2.Equilateral: all sides 5 cm; Isosceles: sides 4, 4, 6; Scalene: sides 3, 5, 7, no equal sides
  3. 3.Equilateral: all sides 5 cm, all angles 60°; Isosceles: —; Scalene: sides 4, 6, 9, no equal sides
  4. 4.Equilateral: sides 6, 6, 6; Isosceles: sides 5, 5, 8, sides 4, 4, 6; Scalene: no equal sides
  5. 5.Equilateral: all angles 60°, sides 6, 6, 6; Isosceles: —; Scalene: sides 4, 6, 9, sides 3, 5, 7

Last reviewed 2026-09-05. Aligned to 5.G.B.3 of the Common Core State Standards for mathematics.