Find the areas of the rectangles whose sides are :
(a) $ 3 \mathrm{~cm} $ and $ 4 \mathrm{~cm} $
(b) $ 12 \mathrm{~m} $ and $ 21 \mathrm{~m} $
(c) $ 2 \mathrm{~km} $ and $ 3 \mathrm{~km} $
(d) $ 2 \mathrm{~m} $ and $ 70 \mathrm{~cm} $

To do:

We have to find the areas of the rectangles whose sides are: (a) $3 \ cm$ and $4\ cm$ (b) $12\ m$ and $21\ m$ (c) $2\ km$ and $3\ km$ (d) $2\ m$ and $70\ cm$.

Solution:

We know that,

The area of a rectangle with length '$l$' and breadth '$b$' is $l \times b$.

Therefore,

(a) Here,

Length $l =4\ cm$ 

Breadth $b =3\ cm$

The area of the rectangle $ = 4\ cm\times3\ cm$

$=12\ cm^2$

(b) Here,

Length $l =21\ m$ 

Breadth $b =12\ m$

The area of the rectangle $ = 21\ m\times12\ m$

$=252\ m^2$

(c) Here,

Length $l =3\ km$ 

Breadth $b =2\ km$

The area of the rectangle $ = 3\ km\times2\ km$

$=6\ km^2$

(d) $1\ m=100\ cm$

This implies,

$1\ cm=\frac{1}{100}\ m$

$ =\frac{70}{100}\ m$

$= 0.7\ m$

Here,

Length $l =2\ m$ 

Breadth $b =0.7\ m$

The area of the rectangle $ = 2\ m\times0.7\ cm$

$=1.4\ m^2$

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Updated on: 10-Oct-2022

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