5th Grade Classifying Two-Dimensional Figures Worksheet Answer Key (PDF)

5th grade classifying shapes worksheet answers – Maths PDF

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This 5th grade classifying shapes worksheet answers covers classifying two-dimensional figures (Common Core 5.G.B.3, 5.G.B.4), with a free PDF to print.

Key takeaway: This answer key helps fifth grade students and parents check shape classification and see the reasoning behind each name.

Topic: Classifying Two-Dimensional Figures (5th grade)
Content: Step-by-step answers to 20 worksheet problems
Standards: 5.G.B.3, 5.G.B.4
Answers: Every step shown, with the method to review
Format: Free printable PDF, US Letter, black and white

This answer key helps fifth grade students and parents check shape classification and see the reasoning behind each name. Also, each solution names the properties used, explains why other names do or do not fit, and writes the most specific name.

The key covers all 20 problems, including the Venn diagram in problem 11 and the tree diagram in problem 12. Then, explanation problems model a complete answer in a sentence. Also, if your answer differs, check which properties the figure has. Then, plan about 15 minutes to compare and fix your work.

Each answer explains which properties decide the name of the figure. When a shape belongs to several groups, the answer shows why. Check that your reasons use sides, angles or parallel lines.

Grade 5 · Common Core State Standards: 5.G.B.3, 5.G.B.4

5th grade classifying shapes worksheet answers: worksheet problems 1 to 10

1 – Name the figure

It has 4 equal sides and 4 right angles. That makes it a square.

Square

2 – Squares and rectangles

A rectangle has 4 right angles and opposite sides equal. Every square has these properties.

True

3 – Rectangles and squares

A rectangle that is 6 cm long and 3 cm wide has 4 right angles, but its sides are not all equal, so it is not a square.

False

4 – Four equal sides

Two pairs of parallel sides make it a parallelogram. Four equal sides make it a rhombus. With no right angles it is not a square.

Rhombus

5 – Properties of parallelograms

Answers can vary. Three correct properties:

It has 4 sides, so it is a quadrilateral.
It has two pairs of parallel sides.
Opposite sides are equal in length.

4 sides, two pairs of parallel sides, opposite sides equal

6 – Triangle with three equal sides

All three sides are 5 cm, so the triangle is equilateral.

Equilateral

7 – Right triangle sides

The sides 3, 4 and 5 are all different: scalene. There is one right angle: right triangle.

Scalene right triangle.

Scalene right triangle

8 – Angles 40, 70, 70

All three angles are less than 90°.

Acute triangle

9 – Angles 30, 30, 120

One angle, 120°, is greater than 90°.

Obtuse triangle

Worksheet problem 10 and after

10 – Sides 6, 6, 9

Two sides are equal and the third is different.

Isosceles

Worksheet problems 11 and up

11 – Place the shapes

The square has both properties, so it goes in the overlap. Also, the 6 by 3 rectangle has only right angles. The rhombus has only equal sides.

Completed Venn diagram.

Rhombus: left only; square: overlap; rectangle: right only

12 – Complete the tree

A parallelogram with 4 right angles is a rectangle.

A tree diagram of the quadrilateral family.

Rectangle

13 – Two pairs of parallel sides

Also, a rectangle, a rhombus and a parallelogram each have two pairs of parallel sides. The trapezoid has only one pair.

A, B and D have two pairs.

Also, a, B and D

14 – Square or rhombus

A rhombus is a quadrilateral with 4 equal sides. A square has 4 equal sides, so it has the main property of a rhombus. The right angles are extra.

A square has 4 equal sides, so it is a rhombus.

15 – Picture frame

Every property fits several groups.

Square (most specific)
Rectangle: 4 right angles
Rhombus: 4 equal sides
Parallelogram: two pairs of parallel sides
Quadrilateral: 4 sides

Square, rectangle, rhombus, parallelogram, quadrilateral

16 – Garden bed

The sides are not all equal, since 8 ft and 3 ft are different. It has four right angles, so it is a rectangle.

Not a square; it is a rectangle

Worksheet problem 17 and after

17 – Road sign

Three equal sides: equilateral. Each angle is less than 90°: acute.

Equilateral and acute

18 – Rhombus must be a square

A rhombus has 4 equal sides, and this one has sides of 5 cm. A square needs 4 right angles. This rhombus has angles of 60° and 120°, so it has no right angle.

Priya is wrong: this rhombus is not a square.

19 – Cutting a triangle

(a) All sides are different: scalene.

(b) One right angle: right triangle.

(a) Scalene; (b) right; (c) 36 in

20 – Quilt patches

(a) Two equal sides: isosceles.

(b) \(5+5+8=18\) inches.

(d) \(28-18=10\).

(a) Isosceles; (b) 18 in; (c) 28 in; (d) the rhombus, by 10 in

Key facts behind this 5th grade classifying shapes worksheet answers

Key facts

Also, a quadrilateral has 4 sides; a parallelogram has two pairs of parallel sides.
Next, a rectangle has 4 right angles; a rhombus has 4 equal sides; a square has both.
Every square is a rectangle and a rhombus, but not every rectangle is a square.
Triangles by sides: equilateral, isosceles, scalene.
Triangles by angles: acute, right, obtuse.

Common mistakes with this 5th grade classifying shapes worksheet answers

Students match the name but skip the reason. The key gives a reason for each name, and explanation problems need one.
Students leave out names in problem 15. A square is also a rectangle, a rhombus, a parallelogram, and a quadrilateral.
Students place the 6 by 3 rectangle in the overlap in problem 11. It has right angles but unequal sides, so it belongs only to rectangles.
Students ignore the difference between sides and angles in problem 19. The key gives separate names for each.

How to use these solutions

Compare the properties you listed with the key’s list. A missing property usually explains a wrong name. Repeat this habit on every problem for the best results.
Redo each missed problem by drawing the shape with marks. The marks show which names fit. Repeat this habit on every problem for the best results.
Parents can ask the child to explain why every square is a rhombus. Repeat this habit on every problem for the best results.

Download the 5th grade classifying shapes worksheet answers as a PDF with the button below and keep it with your notes.

5th grade classifying shapes worksheet answers: frequently asked questions

Is a garden bed that is 8 feet by 3 feet a square?

No. A square needs four equal sides, and 8 feet is not equal to 3 feet. The corners are right angles, so the best name is rectangle. It is also a parallelogram and a quadrilateral.

How is the sign in problem 17 classified?

All three sides are 12 inches, so it is equilateral by sides. Each angle is 60 degrees, which is less than 90, so it is acute by angles. So it is an equilateral, acute triangle.

Why is Priya wrong in problem 18?

A rhombus has four equal sides but not always right angles. A rhombus with sides of 5 centimeters and angles of 60 and 120 degrees has no right angles, so it is not a square.

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