Area And Perimeter

Perimeter and Area of Class 7

There are two different methods for finding the area of this shape:

area and perimeter

Method 1

Divide the shape into squares and rectangles, find their individual areas and then add them together.

area and perimeter

Area = 16 + 16 + 48 = 80cm2

Method 2

Imagine the shape as a large rectangle with a section cut out.

Find the area of the large rectangle (12 × 8) and then subtract the part that has been cut out (4 × 4)

area and perimeter

Area = (12 × 8) - (4 × 4) = 96 - 16 = 80cm2

 

To calculate the area of the C shape, divide the C shape into 3 rectangles:

The area of rectangle 1 can be found by multiplying the two side lengths together:

area and perimeter

12 × 3 = 36 m²

The width of rectangle 2 is missing, this can be found by working out 15 – 10 = 5 m or 12 – 7 = 5m. So the area of rectangle 2 is:

5 × 6 = 30 m²

Finally, work out the area of rectangle 3 by multiplying the two side lengths together:

15 × 3 = 45 m²

So the total area of the compound C shape is:

36 + 30 + 45 = 111 m².

So the perimeter of the C shape is 68m and the area of the C shape is 111m².

If you are finding this difficult take a look at these:

A compound shape is a shape that is made up from other simple shapes. In this article we will be working out the area of a L shape (made up from 2 rectangles). To find the area of a compound shape, follow these simple steps:

Step 1: Work out the missing lengths around the edge of the compound shape.

Step 2: Divide your L shape into two rectangles. This can be done in 2 different ways (both methods will give the same answer).

Step 3: Work out the area of each rectangle. Do this by multiplying the base of the rectangle by the height of the rectangle.

Step 4: Add the areas of the rectangles together to give the total area of the L shape.

You can also find the mind map here 

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