Note : 1. If all the sides are equal but not at right angles to each other, then it
becomes a rhombus.
- The area of square is (side ×^ side) square units.
- Perimeter of a square = 4(side) units.
- Adjacent sides
In a quadrilateral the sides having the common vertex are termed as adjacent sides.
When the child is provided with any quadrilateral either made of plastic or paper,
he/she will be able to understand the idea through exploration supplemented by the
description given by teachers.
- Diagonal
The line joining the opposite vertices of a quadrilateral is called as the diagonal.
Diagonals are of two types, primary diagonal and the secondary diagonal. Primary
diagonal is the one which connects the top left vertex and the bottom right vertex.
Secondary diagonal is the one which connects the bottom left vertex and the top
right vertex.
A neatly cut paper which is in the shape of either a square or rectangle be given to
the child. Facilitate the child to fold the paper in such a way that the opposite
vertices in alternate sides are connected, which is the diagonal.
- Trapezium
A Quadrilateral with a single pair of parallel sides is called as the trapezium. An
embossed diagram of a trapezium be prepared and the child asked to explore its
A B
D C
Primary
Secondary
