ladder resting on a wall

Question

a ladder is resting against a wall. The top of the ladder touches the wall at a height of 12 feet. Find the length of the ladder if the length is 4 feet more than its distance from the wall.

Answer 1

Let L = Length of Ladder

D = Distance of the base of ladder from the wall 

 using right angle triangle

(L)² = D² +12²

But L = D +4 given in question

 

 

(D+4 )² = D² +144

 

D =16 So L=  D +4 = 20ft + length of ladder

l