The ladder forms a right angle triangle with the wall. The straight line distance from the bottom of the window to the ground forms the opposite side. The distance from the bottom of the ladder to the house represents the adjacent side. To determine the required length of the wire, c, we would Pythagorean theorem which us expressed as
10 9/10.... because 10 can be divided into 109 10 whole times with a remainder of 9 so you put the 9 over the original denominator which is 10 so 9 over 10
