Originally Posted by

**Jhevon** Let A be the area, b be the base and h be the height (or altitude)

Let dh/dt be the rate at which the height is changing

Let dhA/dt be the rate at which the area is changing

Let db/dt be the rate at which the base is changing

A = (1/2)bh

when A = 100, h = 10

100 = (1/2)(10)b

=> b = 20

now, A = (1/2)bh

=> dA/dt = (1/2)h db/dt + (1/2)b dh/dt

=> dh/dt = [2dA/dt - h db/dt]/b

now plug in all the values we know

=> dh/dt = [2(2) - 10(1)]/20

=> dh/dt = -3/10

so the base is decreasing at a rate of -3/10 cm/min