CBSE Book Class 6 Maths Activity 11

To determine the number of lines of symmetry of following shapes by paper folding -

(a) equilateral triangle   (b) isosceles triangle

(c) square                    (d) rectangle

(e) rhombus

Learning Objective : To understand line symmetry of plane figures and draw their lines of symmetry.

Pre-requisite : Knowledge of line symmetry of plane figures.

Materials Required : Cutouts of the geometrical figures, equilateral triangle, isosceles triangle square, rectangle and rhombus.

Procedure: 

Step 1. Take a cutout of an equilateral triangle. Fold it through a vertese so that the two parts of the triangle cover each other exactly, Fig 11(a).

Step 2. Unfold and mark the crease or the line of fold. The triangle is said to have a symmetry called line symmetry. This line of fold is called a line of symmetry of the triangle.

Step 3. Fold the triangle again in the same way through other two vertices Fig. 11(b) to get two more lines of symmetry.

Step 4. Now take a cutout of an isosceles triangle and follow Steps 1 and 2 above. Mark the line of symmetry, if any.

Step 5. Repeat the activity by taking cut out of a square, a rectangle and a rhombus. Mark lines of symmetry in each case, if any

Please refer to the link below - CBSE Class 6 Maths Activity 11