Which of the following theorems may be used to locate irrational numbers like $\sqrt{5 },\sqrt{ 10 }$  and $\sqrt{17 }$  on the number line?

It is given that the numbers are $\sqrt{5 },\sqrt{ 10 }$  and $\sqrt{17 }$ .
We know that Pythagoras theorem may be used whenever there are squares and square roots involved.
Now, $5=2^2+1^2$ _,   $10=3^2+1$  _and $17=4^2+1$ _.
Let us consider $\sqrt{17 }$ .
$17=4^2+1$  So, draw a right-angled $\Delta OAB,$  in which OA =4 units and AB =1 unit and $\angle OAB={90}^{°}$ _. By using Pythagoras theorem, we get 
$\begin{array}{l}\mathrm{OB}=\sqrt{{\mathrm{OA}}^2+{\mathrm{AB}}^2}\\ =\sqrt{4^2+1^2}\\ =\sqrt{16+1}\\ =\sqrt{17}\end{array}$ 
Taking $\mathrm{OB}=\sqrt{17}$  as radius and point O as a center, draw an arc which meets the number line at point P on the positive side of it. The point P represents $\sqrt{17 }$  on the number line.