Page 1 - LN1

SAI International School
CLASS-VII

Mathematics
CHAPTER-11: Perimeter and Area
Lesson Notes- 1

SUBTOPIC: Basic Concept and area, perimeter of square and
rectangle

Introduction: Area and Perimeter are very important terms while dealing with
mathematics. This applies to any shapeof the field, irregular or regular.
 Area is the term used to define the amount of space taken up by a
2D shape or surface. We measure area in square units: cm² or m².
 Perimeter is the total length of the boundary of a closed figure.

 In this chapter, we will learn about how to find area and perimeter of a plane
figures. Perimeter is the distance around a closed figure while area is the part
of plane or region occupied by the closed figure.

Area and Perimeter of Squares:A square is a flat shape with 4 equal sides
and every angle is a right angle i.e. 90°.

 In the above figure, ABCD is a square.
Here AB = BC = CD = DA
 Each interior angle is 90°.
 The Perimeter of square is 4 times the side length. Let a be the length of each
side of square.
Now, perimeter of square = 4 x a = 4a
 Area of square = side length squared
= a x a
= a 2

Area and Perimeter of Rectangle: Rectangle is a 4-sided flat shape with
straight sides where all interior angles are right angles (90°).
 Also opposite sides are parallel and of equal length.