Calculus and Ladders

[tonytouch311]

A ladder 20 ft long is leaning against a wall. If the foot of the ladder is being pulled away from the bottom of the wall at a rate of 4 ft per second. At what rate is the top of the ladder moving down the wall the bottom of the ladder is 12 ft from the wall the bottom of the ladder is 12 ft from the wall?

Im not sure hot to even start this

 

[Deleted member 4993]

A ladder 20 ft long is leaning against a wall. If the foot of the ladder is being pulled away from the bottom of the wall at a rate of 4 ft per second. At what rate is the top of the ladder moving down the wall the bottom of the ladder is 12 ft from the wall the bottom of the ladder is 12 ft from the wall?

Im not sure hot to even start this

Draw picture.

Call the corner of the wall&floor - the origin.

Then

the distance to the top of the ladder is height (h).

the distance to the end of the ladder(on the floor) is the base(b).

Call the length of the ladder - L

find relation between h, b & L - invoking Pythgorus.

Now what.....