Question

Question 39

The perimeter of a rectangle becomes ___ times its original perimeter if its length and breadth are doubled.

Answer 1

2 times

Perimeter of a rectangle with length l and breadth b, $P=2(l+b)$

If the length and the breadth are doubled, then the new length is $2l$ and the new breadth is $2b$.

Therefore, the new perimeter is

$=2\left[\right(2l+2b\left)\right]$

$=2\left[2\right(l+b\left)\right]$

$=2\left[P\right]$

Hence, the perimeter becomes 2 times the original perimeter.