What is the value of x?

x = 41 cm
Here is why:
For this question we have to use the pythagorean theorem, which is used for right triangles. The hypotenuse will always be the last in this theorem.
[tex]a^2+b^2=c^2[/tex]
Plug in.
[tex]9^2+40^2=c^2[/tex]
[tex]81+1,600=c^2[/tex]
Add together.
[tex]1,681=c^2[/tex]
Now we will find the square root of 1,681, since c is squared.
[tex]\sqrt{1,681}[/tex]
= 41 cm