Creo que lo habia hecho asi:

$$\frac{1600}{h^2} + h^2 = 100\frac{1600 + h^4}{h^2} = 100h^4 - 100h^2 - 1600 = 0\textrm{Sustituyo } h^2 = t \Rightarrow h = \sqrt{t} \ \ (h > 0)t^2 - 100t + 1600 = 0 \Leftrightarrow h = 2\sqrt{5}\ \vee \ h = 4\sqrt{5}\therefore\ S = \{2\sqrt{5}, 4\sqrt{5}\}$$