We can notice the triangle given is a special triangle, a 45°- 45°- 90° triangle. The hypotenuse of a 45°- 45°- 90° is √2 times the length of a side. We can set up the equation(using x as the side):
x * √2 = 22
We can divide by √2 on both sides to get:
x = 22 / √2
To rationalize the denominator, we multiply by √2 / √2 on the right side: