Hi guys. Suppose we have an equilateral with the side = 4.

My book says that the height of an equilateral = $\displaystyle \frac{s\sqrt{3}}{2}$

And we get 4(1.4)/2 = 2.8 = h

Then let's say we divide the equilateral by its height. We then get two right triangles, each with the sides 2, and the hypotenuse 4. Now we want to calculate its height. We do

$\displaystyle 2^2 + h^2 = 4 + h^2 = 16 = h^2 = 12$, and h is not equal to 2.8 (how do i type "not equal to"?).

What have I misunderstood?