The angle of a sector of a circle is 75°. If the radius of this circle is increasing at the rate of 0.3cm/s find the rate of increase of the area when the radius is 6cm
change the units from degrees to radians. The area is
a = 1/2 r^2 θ = 5/24 πr^2
da/dt = 5/12 π r dr/dt
so plug in your numbers,