Area And Perimeter
Perimeter and Area of Class 7
There are two different methods for finding the area of this shape:
Divide the shape into squares and rectangles, find their individual areas and then add them together.
Area = 16 + 16 + 48 = 80cm2
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 = (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:
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