Red Swastika School P5 CA1 2008 Math Paper 2 (Q15)

The figure below is made up of five identical rectangles. If the toal area of the figure is 540 square cm, find the perimeter of one rectangle.



Solution

Area of 1 rectangle ----- 540 square cm divided by 5 = 108 square cm



Length of rectangle is 3 times breadth rectangle, therefore, we can divide 1 rectangle into 3 equal parts as shown above.

The area of 1 square above ----- 108 square cm divided by 3 = 36 square cm

The side of this 1 unit square has to be 6 cm (6 x 6 = 36)

Since 1 side of the square is 6 cm, the length of 1 rectangle is -----
6 cm x 3 = 18 cm

The perimeter of 1 rectangle is therefore,

18 cm + 6 cm + 18 cm + 6 cm = 48 cm

Answer: The perimeter of one rectangle is 48 cm.