Question

The altitude of a triangle is increasing at a rate of 1 cm?min while the area of the triangle is increasing at a rate of 2 cm^2/Min. At what rate is the base of the triangle changing when the altitude is 10 Cm and the area is 100cm^2?

Answer 1

I know my given rates are dx/dt = 1cm^2/Min, dA/dt =2 cm^2/min.
I need to find dy/dt when dx/dt x=10cm and dA/dt when x 100 cm^2
equation that relates all I have a=1/2 ah.
andthe picture I drew

from the equation I solved for y and took its derivative

A=1/2 xy <=> y = 2A/x <=> dy/dt = 2dA/dt / dx/dt

and that's as far as I have gotten. If I replace the values for x=10 and A=100 I do not get the correct answer.

Where I am doing wrong?