Skip to content
Brainsladder

Recognize and Identify Lines of Symmetry in Figures

Students learn that a line of symmetry divides a figure into two congruent, mirror-image halves. Students identify whether given two-dimensional figures have a line of symmetry and determine the total number of lines of symmetry a figure has.

Try three of them

Real questions from this skill, graded here. No account, and nothing is saved.

Recognize and Identify Lines of Symmetry in Figures

Grade 4 · Line Symmetry · question 1 of 3

0 of 20

20 rungs. A star at the top.

12

Only one dashed line folds the flag onto itself. Which?

Which line? Type its number.

How it is taught

0:00 of 3:33

A line of symmetry is a fold that makes matching halves.

The two halves are mirror images.

12

Read it: Fold it so the halves match

Fold this rectangle along line 1 and every corner lands on a matching corner, so line 1 is a line of symmetry.

  1. Try one line at a time, and picture folding the shape along it.
  2. Count the corners on each side of the line.
  3. Call it a line of symmetry only if every corner lands on a matching corner.

A line of symmetry cuts a shape into two halves that are mirror images.

If one side has more corners than the other, the halves cannot match.

Some shapes have several lines of symmetry, and some have none at all.

A line of symmetry folds a shape onto itself, every corner on a matching corner.

Calling the rectangle's diagonal a line of symmetry because it cuts the shape in half.

Fold along the diagonal and the corners miss each other. Equal halves are not enough: they must match when folded.

How many lines of symmetry does a square have? — 4. A square folds onto itself up and down, across, and along both diagonals: 4 lines.

Rectangle — how many lines of symmetry?

A line of symmetry is a fold line that splits a shape into two halves that match exactly.

Let's check this rectangle. How many lines of symmetry can we find?

Grade 4 · Find every fold that splits a rectangle into matching halves

First, let's try folding across the middle, side to side.

The top half matches the bottom half exactly. That's one line of symmetry!

Now let's try folding straight down the middle, top to bottom.

The left half matches the right half. That's another line of symmetry!

What about a diagonal fold, corner to corner?

The corners don't line up — the halves don't match. So this is NOT a line of symmetry.

Only two folds split the rectangle into matching halves.

A rectangle has exactly two lines of symmetry. Nice work!

Now you try. Count the lines of symmetry on this figure. How many fold lines?

What you see

While they climb, your page writes one true line to ask about tonight, and a short note each Sunday.

MayaGrade 3 · Mathematics
Did you know?

A chessboard has 64 squares — share them out between the 8 rows and each row holds exactly 8.

Today’s goal
1 star — one skill mastered, every rung of its ladder climbed
Climbing now
Divide within 100

An example student.

MayaGrade 3 · Mathematics

Maya earned 2 stars this week — Interpret multiplication as equal groups, which took 6 answers over 3 days before its star landed 3 days ago and Multiply by 6, 7, 8 and 9. Next up: Divide within 100.

An example week.

More of the library

Every skill has a page

Practise this skill free

14 days of every skill, practice packets, Fluency sheets and up to four students. No card.

Start free