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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 15 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: sides 6, 6, 6, sides 3, 5, 7, no equal sides, two equal angles

EquilateralIsoscelesScalene
2.Sort each one into the right box.

Sort: sides 4, 6, 9, no equal sides, sides 6, 6, 6, two equal angles

EquilateralIsoscelesScalene
3.Sort each one into the right box.

Sort: sides 4, 6, 9, all angles 60°, sides 6, 6, 6, sides 4, 4, 6

EquilateralIsoscelesScalene
4.Sort each one into the right box.

Sort: sides 5, 5, 8, sides 6, 6, 6, sides 4, 4, 6, all sides 5 cm

EquilateralIsoscelesScalene
5.Sort each one into the right box.

Sort: all sides 5 cm, sides 5, 5, 8, sides 4, 4, 6, sides 4, 6, 9

EquilateralIsoscelesScalene

LessonPrint · 5.G.B.3 · Set 15 · free to copy for classroom use

Answer key — Triangles by Sides

Set 15. Prints on its own sheet.

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

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