The breadth of a cuboid is $$\frac{2}{3}$$ of its length and its height is $$\frac{3}{4}$$ of its breadth. If its volume is 72 cu.mts, then its surface area. in sq.mts, is
As per given question,
volume of cuboid=72 cu. mts
Let the length of the cuboid be$$=x$$
breadth$$=\dfrac{2}{3}\times x$$
then height$$=\dfrac{3}{4}\times \dfrac{2}{3}\times x$$
as we know volume of cuboid$$= length \times breadth \times height$$
$$\Rightarrow x\times \dfrac{2}{3}\times x \dfrac{1}{2} \times x$$
$$\dfrac{1}{3}\times x^3=72$$
$$x^3=216$$
x=6
then length=6
breadth$$=\dfrac{2}{3}\times 6=4$$
height$$=\dfrac{3}{4}\times \dfrac{2}{3} \times 6=3 $$
as we know suface area of cuboid$$=2(lb+bh+hl)$$
surface area$$=2(6\times 4+4\times 3+3\times 6) $$
surface area= 108 sq.mts
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