How do you calculate the height of an equilateral triangle?

1 Answer
Nov 26, 2015

The height of the equilateral triangle is h=(asqrt(3))/2

Explanation:

If you draw a height in an equilateral triangle you can see that the triangle is divided in 2 right angled triangles in which: sides a are hypothenuses, height is one cathetus (common for both triangles), the other is equal to a/2, so if we use the Pythagorean theorem we get:

(a/2)^2+h^2=a^2

h^2=a^2-(a/2)^2

h^2=a^2-a^2/4

h^2=3/4a^2

h=(asqrt(3))/2