Question

height of equilateral triangle with side x?

Answer 1

if you know the formula use it or do by pythagoras theorem 
ex :
by Pythagoras theorem 
if sides of eq. tri. is x
hyp= x
base= x/2
and the h= √3x square/4

Answer 2

height of equilateral triangle is always = √3/4

so u no need to find, put this value and solve question.