Question

If a 4 cuboids of dimension $4.2$ cm $\times$ $2.8$ cm $\times$ $7.5$ cm each is stacked sideways, what will be the lateral surface area of the newly formed prism?

• A. $294$ cm${}^2$
• B. $383$ cm${}^2$
• C. $267$ cm${}^2$
• D. $337$ cm${}^2$

Answer 1

The correct option is A $294$ cm${}^2$

The dimensions of the individual cuboids are:
Length $=l=4.2$ cm,
Breadth $=b=2.8$ cm, and
Height $=h=7.5$ cm


When $4$ of these are stacked sideways, they will form a new cuboid like this:


Dimensions of the new cuboid will be:
New Length $l=4.2+4.2+4.2+4.2=16.8$ cm
Breadth $b=2.8$ cm
Height $h=7.5$ cm
$(\because \text{Breadth and Height remains the same})$

$\therefore$ Its lateral surface area $=2(l+b)h$
$=2(16.8+2.8)7.5$
$=2\left(19.6\right)7.5$
$=39.2\times 7.5=294$ cm${}^2$