Question

Question 3

The side of a square is 10 cm. How many times will the new perimeter become, if the side of the square is doubled?

(a) 2 times

(b) 4 times

(c) 6 times

(d) 8 times

Answer 1

Given, side of a square = 10 cm

We know that, perimeter of a square = 4 $\times$side length = 4$\times$10

= 40 cm

$\therefore$ Perimeter of old square= 40 cm

Now, according to the question, side of the square is doubled.

$\therefore$ New side length = 2$\times$10

= 20 cm

Again, perimeter of new square = 4$\times$ new side length

= 4$\times$20

= 80 cm

$\therefore \frac{\text{New~perimeter}}{\text{Old perimeter}}=\frac{80}{40}=2$

$\Rightarrow \text{New perimeter}=2\times \text{Old perimeter}$

Hence, the new perimeter is 2 times of the old perimeter i.e option (a).