Question 491915
For an equilateral triangle, When you draw the perpendicular angle bisector, you will obtain a 30 -60 -90 triangle with one of the sides as the hypotenuse, which is s
The height, opposite the 60 degree angle, is s*{{{sqrt(3)}}}/2.
Therefore f(x) = x*{{{sqrt(3)}}}/2.
So, it follows f(3) = 3*{{{sqrt(3)}}}/2. This will be the height with a side of 3.
Cleomenius.