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Triangles by Sides is a free printable Grade 5 math 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 students in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.

Set 1 of 25 · the same problems every time you open this link.

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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 3, 5, 7, sides 4, 4, 6, sides 6, 6, 6, sides 5, 5, 8

EquilateralIsoscelesScalene
2.Sort each one into the right box.

Sort: all sides 5 cm, sides 6, 6, 6, two equal angles, sides 4, 6, 9

EquilateralIsoscelesScalene
3.Sort each one into the right box.

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

EquilateralIsoscelesScalene
4.Sort each one into the right box.

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

EquilateralIsoscelesScalene
5.Sort each one into the right box.

Sort: two equal angles, no equal sides, sides 3, 5, 7, all sides 5 cm

EquilateralIsoscelesScalene

LessonPrint · 5.G.B.3 · Set 1 · free to copy for classroom use

Answer key — Triangles by Sides

Set 1. Prints on its own sheet.

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

Questions about Triangles by Sides

What does the Triangles by Sides worksheet cover?

It practices classifying triangles — 5 questions for Grade 5, all on Common Core 5.G.B.3: Understand how shape categories fit inside one another. The instruction to students is “Sort each one into the right box”, and the answer key follows on the next sheet.

Which Common Core standard does Triangles by Sides practice?

CCSS.MATH.CONTENT.5.G.B.3 — 5.G.B.3, under Geometry for Grade 5. The published standard reads: “Understand that attributes belonging to a category of two-dimensional figures also belong to all subcategories of that category.” The worksheet assesses that standard rather than a paraphrase of it.

What age or grade is this worksheet for?

Triangles by Sides is written for Grade 5, typically ages 10-11. It is one of the sheets on 5.G.B.3, so it suits any student working at that standard — including older students revisiting it and younger ones working ahead.

Does Triangles by Sides come with an answer key?

Yes. All 5 answers are generated from the same problems as the questions, so the key cannot drift out of step with the sheet. It starts on a fresh sheet of paper, after the questions, so it is not handed out with the class by accident.

How many different versions of Triangles by Sides can I print?

25 — one per student, and all 25 ask different questions. Set 1 downloads the whole class as a single PDF. Every version is fixed to its own address, so a sheet printed today holds the same problems when you reopen it next week.

Is Triangles by Sides free to print and photocopy?

Yes. Triangles by Sides, its answer key and its 25 versions are free to print and photocopy for your own class, with no account, no email capture and no subscription at the download step. Please do not resell them or republish them as your own.

More practice for 5.G.B.3

Understand how shape categories fit inside one another.

All Grade 5 worksheets

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