Lines of symmetry
for 5th grade

Which shape has more lines of symmetry?

Lines of symmetry are imaginary lines that you can draw through a shape that divide the shape into two halves that are exact mirror images of each other. Different shapes have different numbers of lines of symmetry.

Square: A square has four sides of equal length and four right angles. It has four lines of symmetry - one vertical, one horizontal, and two diagonal lines. Each line of symmetry divides the square into two halves that are mirror images of each other.

Rectangle: A rectangle has two pairs of opposite sides of equal length and four right angles. It has two lines of symmetry - one vertical and one horizontal.

Triangle: The number of lines of symmetry a triangle has depends on the type of triangle it is. An equilateral triangle has three sides of equal length and three equal angles. It has three lines of symmetry - one vertical and two diagonal lines. An isosceles triangle has two sides of equal length and two equal angles. It has one line of symmetry - the line that goes through the midpoint of the base and bisects the opposite angle. A scalene triangle has no lines of symmetry.

Kite: A kite is a quadrilateral with two pairs of adjacent sides of equal length. It has one line of symmetry - the line that goes through the midpoint of the shorter diagonal and bisects the longer diagonal.

Pentagon: A regular pentagon has five sides of equal length and five equal angles. It has five lines of symmetry - one vertical, one horizontal, and three diagonal lines. Regular shapes with more sides like hexagon and octagon have the same number of lines of symmetry as they have sides. So a regular octagon has 8 and a regular nonagon has 9.

In this topic you are given diagrams of pairs of shapes and must decide which of the shapes has more lines of symmetry. The shapes include square, rectangle, kite, various types of triangle, parallelogram, pentagon, heptagon, etc.