Question

8. The perimeter of a rectangle is equal to
the perimeter of the square of side 15 cm.
If the side of the rectangle is 20 cm long,
what is its breadth?​

Answer 1

Given side of a square =15cm

side of rectangle=20 cm

breadth=?

:To find breadth

Solution:

perimeter of square= 4×sides

=>15×4=60cn

perimeter of rectangle=perimeter of square

=>2(l+b)=60

=>2(20+b)=60

=> 2(20+b)=60

=>2b=60-40

=>2b=20

=20/2

=10cm

:breadth=10cm

Hence length of rectangle is 20cm and breadth is 10 cm

Answer 2

Answer :

The breadth of the rectangle is 10cm.

Explanation :

Given that,

Perimeter of a rectangle = Perimeter of square

Or,

$\implies 2(l + b) = 4a$

Where,

• $a$ denotes the each side of the square is 15cm.
• $l$ denotes length of the rectangle is 20cm(given). And assuming the breadth as $b$

So, we need to find the breadth of the rectangle.

According to the question :

$\implies 2( l + b )= 4a$

$\implies \: 2(20 + b) = 4(15)$

$\implies \: 2(20 + b) = 60$

$\implies \: 20 + b = \frac{60}{2}$

$\implies \: 20 + b = 30$

$\implies \: b = 30 - 20$

$\implies \boldsymbol{b = 10}$

Therefore the breadth is 10cm.