- Rectangle
In a quadrilateral, if the opposite sides are equal and all the four angles are equal to
90 o or a right angle then it is called a rectangle.
A hard board in the shape of a rectangle can be given to the child to explore. Otherwise,
a neatly cut paper in the shape of a rectangle may be used to explain this concept.
Note : 1. In a rectangle the two pairs of opposite sides are equal. The longer side is
the length and the shorter side is the width.
- Area of rectangle = (length x width) square units
- Perimeter of a rectangle = 2 (length + width) units
- Cyclic quadrilateral
If all the four vertices of a quadrilateral lie on the circumference of a circle, then the
quadrilateral is said to be a cyclic quadrilateral.
Verbal explanation of the idea along with the construction of a cyclic quadrilateral by
the child as mentioned in the creative mathematics section will enable the child to
understand the idea clearly.
- Area of a quadrilateral
Any quadrilateral can be made into two triangles by its diagonals. The area of
the quadrilateral can be found by adding the areas of the triangles by any such
division.
A B
D C
