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प्रश्न
The height of an equilateral triangle is 6 cm. Find its area.
उत्तर
Let the side of the equilateral triangle be x cm.
As, the area of an equilateral triangle = `sqrt3/4 "(side)"^2=(x^2sqrt3)/4`
Also, the area of the triangle =`1/2xxBasexxHeight=1/2xx x xx6=3x`
So, `(x^2sqrt3)/4=3x`
⇒` (xsqrt3)/4=3`
⇒`x=12/sqrt3`
⇒`x=12/sqrt3xxsqrt3/sqrt3`
⇒`x=(12sqrt3)/3`
⇒` x=4sqrt3 cm`
Now, area of the equilateral triangle =3x
=`3xx4sqrt3`
=`12sqrt3`
=`12xx1.73`
=`20.76 cm^2`
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