what is the value of x?

To solve this you must use Pythagorean theorem:
[tex]a^{2} +b^{2} =c^{2}[/tex]
a and b are the legs (the sides that form a perpendicular/right angle)
c is the hypotenuse (the side opposite the right angle)
In this case...
a = 9
b = 40
c = x
^^^Plug these numbers into the theorem
[tex]9^{2} +40^{2} =x^{2}[/tex]
simplify
81 + 1600 = [tex]x^{2}[/tex]
1681 = [tex]x^{2}[/tex]
To remove the square from x take the square root of both sides to get you...
41 = x
Hope this helped!
~Just a girl in love with Shawn Mendes