4th Grade Lines of Symmetry Test Answer Key and Scoring Guide (PDF)

4th grade lines of symmetry test answer key – Maths PDF

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This 4th grade lines of symmetry test answer key covers lines of symmetry (Common Core 4.G.A.3), with a free PDF to print.

Key takeaway: This answer key helps fourth grade students see how each point on the symmetry test was earned.

Topic: Lines of Symmetry (4th grade)
Content: Worked solutions and a scoring guide for 8 questions
Standards: 4.G.A.3
Answers: Every step shown, with the method to review
Format: Free printable PDF, US Letter, black and white

This answer key helps fourth grade students see how each point on the symmetry test was earned. Also, it gives full solutions to all eight questions, with every line of symmetry described and the reasoning for each count.

Question 3 shows where all five lines of the pentagon go, question 5 describes the completed figure, and question 8 gives two counterexamples to Mei’s claim. Add your points out of 20, then spend about 15 minutes redoing every question that lost credit. Then, fold a paper copy of each shape to confirm.

Use this answer key to score the test out of 20 points. Each solution explains the fold that makes the halves match. The scoring note tells how to give partial credit for drawings and explanations.

Grade 4 · Common Core State Standards: 4.G.A.3

4th grade lines of symmetry test answer key: worked solutions

1 – Line symmetric or not [2 pts]

So, a kite folds along its long diagonal so the halves match: yes.
A slanted parallelogram has no fold that makes the halves match: no.

Scoring: 1 point for each correct answer.

2 – Count the lines [2 pts]

2 lines
3 lines

Scoring: 1 point for each correct answer.

3 – Draw the lines [2 pts]

The five lines each join a corner to the middle of the opposite side.

A regular pentagon.

Scoring: 1 point for drawing at least 3 correct lines, 2 points for all 5 correct lines and no incorrect lines.

4 – Letters with symmetry [2 pts]

A, H, and M can be cut into matching left and right halves by a vertical line.

A, H, M

Scoring: 2 points for all three letters with no extra letters. 1 point for two correct letters, or for all three plus one extra.

5 – Complete the figure [3 pts]

Each corner on the left matches a corner on the right at the same distance from the dashed line.

Grid with a dashed line of symmetry.

Scoring: 1 point for correct corners on the right half, 1 point for matching heights, and 1 point for joining the corners in the correct order.

6 – Sort the shapes [3 pts]

(a) 1 line. (b) A regular hexagon has 6 sides, so 6 lines. (c) No fold matches, so 0 lines.

(a) 1 (b) 6 (c) 0

Scoring: 1 point for each correct number.

Question 7 and after

7 – Road signs [3 pts]

8 sides, so 8 lines
3 sides, so 3 lines
\(8 – 3 = 5\), so 5 more lines

Scoring: 1 point for each correct part.

8 – Check a claim [3 pts]

Mei is not right. A square has 4 lines of symmetry, but a rectangle that is not a square has only 2, and a slanted parallelogram has 0.

No, she is not right.

Scoring: 1 point for saying she is not right, 1 point for a correct example with the right number of lines, 1 point for a second correct example.

Total score

Total

20 points

Key facts behind this 4th grade lines of symmetry test answer key

Key facts

A line of symmetry splits a figure into two matching halves.
Also, a square has 4 lines of symmetry, a rectangle has 2, and an equilateral triangle has 3.
A regular polygon with n sides has n lines of symmetry.
Then, some figures, like a slanted parallelogram, have no lines of symmetry.
Check by folding: the edges and corners must line up exactly.

Common mistakes with this 4th grade lines of symmetry test answer key

Students lose points because a line is missing. Instead, count the lines against the key and look for the one you skipped.
Students give one example in question 8. Also, the question asks for two examples, and each is scored.
Students ignore part of question 7. Instead, both the stop sign and the yield sign are needed. Slow down at that step and check it twice.
Students draw the figure in question 5 without matching the points. Also, compare each corner with the key.

How to learn from your test

Sort lost points into counting lines, drawing lines, and explaining. Practice the weakest group first. Repeat this habit on every problem for the best results.
Redo question 6 with new shapes, such as a kite and a rhombus. Also, new shapes show whether you can apply the idea.
Teachers can ask students to trade drawings and check each other’s lines with a fold. Repeat this habit on every problem for the best results.

Download the 4th grade lines of symmetry test answer key as a PDF with the button below and keep it with your notes.

4th grade lines of symmetry test answer key: frequently asked questions

How many lines does a regular hexagon have?

A regular hexagon has 6 lines of symmetry. So, three lines join opposite corners, and three join the midpoints of opposite sides. A regular polygon always has as many lines as sides. A quick check like this takes only a few seconds and prevents most errors.

Why does an isosceles triangle have one line?

Only one fold makes the two equal sides match. The line goes from the top corner to the middle of the base. An equilateral triangle has three lines, but an isosceles one with two equal sides has just one.

What are two examples that disprove Mei’s claim?

A rectangle that is not a square has 2 lines, and a slanted parallelogram has none. Both have four sides, but neither has four lines. One counterexample is enough, but two make the explanation stronger.

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