how do you state the value of a hypotermuse

I think you mean 'hypotenuse' not 'hypotermuse'.

The value of a hypotenuse can be stated by the Pythagorean theorem.

$${\sqrt{{{\mathtt{a}}}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{b}}}^{{\mathtt{2}}}}} = {{\mathtt{c}}}^{{\mathtt{2}}}$$