Assuming that the house is perpenidcular to the ground on which the ladder stands, use the Pythagorean Theorem for the sides of right triangles:

a^{2} + b^{2} = c^{2}

In this problem a = 18, b is the unknown, and c is the length of the ladder (the hypotenuse of the triangle).

18^{2} + b^{2} = 22^{2} or

b^{2} = 22^{2} - 18^{2}

b^{2} = 484 - 324

b^{2} = 160

** b = √160 = 12.6 ft.**

(It would be hard to climb that ladder because it is farther away from the wall than the height of the place where it touches the house)