"How fast is the area of the triangle formed by the ladder, the house, and the ground when the base of the ladder is 7 ft. away from the wall?

Question

Given
h=24ft.
dh/dt=-7/12ft. per sec.
b=7 (base)
db/dt=2ft. per sec.

d/dt[A=1/2bh]

How would you derive this with respect to time?

Answer 1

A= 1/2 bh
dA/dt= 1/2 hdh/dt + 1/2 bdb/dt

compute, you have h, dh/dt, b, db/dt

Answer 2

thanks