halp

hi notsmart2.0!

firstly, we can find the length of the leg of the smaller right triangle. 

$1^2+x^2=5^2$

$1+x^2=25$

$x^2=24$

$x=\sqrt{24}$

now, we can find the value of ? since we have both side lengths of the right triangle.

$(\sqrt{24})^2+5^2=?^2$

$24+25=?^2$

$49=?^2$

$\boxed{?=7}$

i hope this helped you!

:)