Question

If the area of an equilateral triangle is `81sqrt(3)  cm^2`, find its height.

Answer 1

Area of equilateral triangle=`81sqrt3 cm^2` 

Area of equilateral triangle =`(sqrt3/4xxa^2)` where a is the length of the side  

⇒ `81sqrt3=sqrt3/4xxa^2` 

⇒`324=a^2` 

⇒ `a=18 cm` 

Height of triangle=`sqrt3/2xxa` 

=`sqrt3/2xx18` 

=`9sqrt3 cm`