Area

Area measures the surface of something

To find out how much shape is inside we can count the squares. The area of a shape is the amount of space inside it. The area of the shape is 18cm2.

12cm2 What is the area of each of these shapes? Your teacher will give you copy of the worksheet. 26cm2 26cm2

Area of Rectangle Using formula D C 2 A B 4 The area of a rectangle is determined by multiplying length x width. 2 x 4 = ______

Now the area of the rectangle = Total number of squares. = Number of squares in 2 rows. = 4 + 4 = 4 x 2 = (length x breadth) sq. units Usually we denote length as ‘l’, breadth as ‘b’   Area of a rectangle = (l x b) sq. units

Example 1: Find the area of a rectangle whose length is 4 cm and breadth 8 cm Solution: Area of a rectangle = length x breadth = 4 cm x 8 cm = 32 sq. cm 4 8

Example 2: Find the area of a rectangle whose length is 5 cm and breadth 12 cm Solution: Area of a rectangle = length x breadth = 5 cm x 12 cm = 60 sq. cm

Find the area of these rectangles. 1 6 2 2 3 5 4 3

You find the area of a square by multiplying the side by itself. 3

AREA OF SQUARES USING FORMULA: We know that in a rectangle if the length is equal to the breadth, it is a square. They are called the sides of a square. Length = breadth = side of the square Area of a square = length x breadth = (side x side) sq.units Area of the square = (s x s) sq. units

Example 1: Find the area of a square of side 7 cm. Solution: Area of a square = side x side = 7cm x 7cm = 49 sq. cm. 7

Example 2: Find the area of a square of side 12 cm. Solution: Area of a square = side x side = 12cm x 12cm = 144 sq. cm.

Find the area of these squares. 25 5 12 16 8

Area of a Triangle 3 4 Finding the area of a triangle is different. Area of a triangle = ½ (base x height) ***(Base x height) is the same as (length x width).***

Area of a Triangle Sometimes it makes it easier to remember if you can imagine it like this: A triangle is half of a rectangle or square. This is because the base (4) x the height (3) would be the same as the length x the width of a rectangle. 3 4

Example 1: Find the area of Triangle whose height is 8cm and base is 5cm. Solution: Area = ½ x (base x height) = ½ x (5 x 8) = ½ x 40 = 40/2 = 20 sq.cm 8 5

Example 1: Find the area of Triangle whose height is 12cm and base is 8cm. Solution: Area = ½ x (base x height) = ½ x (8 x 12) = ½ x 96 = 96/2 = 48 sq.cm

Find the area of these triangles. 3 4 7 8 2 5 3 6