If the height of an equilateral triangle is $20\sqrt{2}$ cm, then what is its area (in cm2)?
Answer & explanation
Correct answer: option 3
We know that,
Area of a equilateral triangle = \(\frac{\sqrt {3}}{4}\) × (side)2
and, the height of equilateral triangle = \(\frac{\sqrt {3}}{2}\) × (side)
We have,
the height of an equilateral triangle is $20\sqrt{2}$ cm
\(\frac{\sqrt {3}}{2}\) × (side) = $20\sqrt{2}$
side = \(\frac{40\sqrt{2}}{\sqrt {3}}\)
So, Area of a equilateral triangle = \(\frac{\sqrt {3}}{4}\) × (\(\frac{40\sqrt{2}}{\sqrt {3}}\))2
= $\frac{800}{3}\sqrt{3}$