Primary 4 Line Symmetry
A figure has line symmetry when it can be folded along a line so that both halves match exactly. The fold line is called a line of symmetry.
Keywords
- Line of symmetry
- A fold line where the two halves match exactly.
- Symmetrical
- A figure with at least one line of symmetry.
- Mirror image
- The matching part on the other side of the line.
- Grid space
- One square used to count equal distances from the line.
Find and count lines of symmetry
Imagine folding each figure. If both halves land exactly on one another, the fold is a line of symmetry. Count every different fold line that works.
Is it symmetrical? How many lines?
Choose a figure. A line counts only when the two halves match exactly after folding.
Predict whether this figure has a fold line. Reveal each line to count it.
Try together
Does a rectangle have a diagonal line of symmetry?
Reveal the answer
No. A rectangle has two lines of symmetry, through the midpoints of opposite sides. Its diagonals are not fold lines.
Complete a symmetric figure
Use the given line as a mirror. For each corner, count how many grid squares it is from the line, then put its matching corner the same number of squares away on the other side.
Complete the figure on a square grid
The left half is given. Draw its mirror image on the right of the dashed line. Each grid space is one square.
The dashed vertical line is the line of symmetry. Count squares from each left corner to this line.
Printable symmetry grids
