calculus
posted by kristina .
A conical party hat made out of cardboard has a radius of 4cm and a height of 12cm. When filled with beer, it leaks at the rate of 4cm^3/min. (a)At what rate is the level of the beer failing when the beer is 6cm deep? (b) When is the hat half empty?

voluemcone=1/3 h*PI*r^2
but r=h/4
volume=1/3 PI h^3/16 check that
dv/dt= you do it, solve for dh/dt