Question

Find the breadth of the rectangle whose perimeter is $160cm$ and whose length is:
(a) $25cm$
(b) $60cm$
(c) $56.5cm$

Answer 1

Given:

Perimeter of rectangle $160cm$

In a rectangle, if

Length $=l$, Breadth $=b$ Then

Perimeter of rectangle $=2(l+b)$

$\Rightarrow 2(l+b)=160cm$

$\Rightarrow 2(l+b)=160cm$

$\Rightarrow l+b=\frac{160cm}{2}$

$\Rightarrow l+b=80cm$---(1)

Now, lets evaluate the breadth based on the values of given lengths.

(a)

$l=25cm$

From (1)

$l+b=80cm$

$\Rightarrow 25cm+b=80cm$

$\Rightarrow b=80cm-25cm$

$\therefore b=55cm$

(b)

$l=60cm$

From (1),

$l+b=80cm$

$\Rightarrow 60cm+b=80cm$

$\Rightarrow b=80cm-60cm$

$\therefore b=20cm$

(c)

$l=56.5cm$

From (1),

$l+b=80cm$

$\Rightarrow 56.5cm+b=80cm$

$\Rightarrow b=80cm-56.5cm$

$\therefore b=23.5cm$