Answer:
Distance between bottom of the wall and bottom of the ladder = 7 ft
Length of the ladder = 19 ft
Let the distance between the ground and top of the ladder be x
Using Pythagoras theorem,
x^2 + 7^2 = 19^2
x^2 + 49 = 361
x^2 = 312
Therefore x = √312 = 2√78 ft