Question

The area of an equilateral triangle is
$81 \sqrt{3}$
cm?. Find its side.

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Answer 1

Step-by-step explanation:

$Area\: of\: equilateral\: triangle = \frac{\sqrt 3}{4} \times (side)^2 \\ \therefore \: 81 \sqrt 3=\frac{\sqrt 3}{4} \times (side)^2 \\ \implies \: (side)^2= \frac {81 \sqrt 3 \times 4}{\sqrt 3}\\ \implies \: (side)^2= {81 \times 4}\\ \implies \: side=\sqrt {81 \times 4}\\ \implies \: side= {9 \times 2}\\ \implies \: side= 18 \: cm.$

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