Question

Here is a rectangle abcd the length of the rectangle is increased by 10%

Answer 1

If a rectangles length is increased by 10% and the breadth is decreased by 5%, what will be the effect on.

Let the length of rectangle = l and

The breadth of rectangle = b

Solution:

∴ The area of rectangle = l × b

The new length of rectangle = l + 10 % of l

= (1.1)l

The new breadth of rectangle = b - 5 % of b

= (0.95)b

∴ The new area of rectangle = (1.1)l × 0.95)b

= (1.045)lb

Increase in area =  (1.045)lb - lb

= (0.045)lb

∴ The increase in the percentage of area = $\dfrac{(0.045)lb}{lb} \times 100$

= 0.045 × 100

= 4.5 %

Thus, the increase in the percentage of area is "4.5 percent (%)".