Explanation:
that height splits GK (32) into 2 parts :
8 and 32-8 = 24
then we use the geometric mean theorem for right-angled triangles
height = sqrt(p×q)
with p and q being the parts of the Hypotenuse.
so,
height = sqrt(8×24) = sqrt(192)
and now we can use Pythagoras
c² = a² + b²
with c being the Hypotenuse (the side opposite of the 90° angle), a and b are the legs,
to get HK.
HK² = height² + 24² = 192 + 576 = 768
HK = sqrt(768)