Question

The volume of a cone varies jointly with the area of the base and the height. When the area of the base is 27 cm2 and the height is 6 cm, the volume is 54 cm3. Therefore, the area of the base is _ cm^2 when the height is 12 cm and the volume is 124 cm^3.

Answer 1

cone=cup:
V=124cm^3.
h=12cm
V=Bh
P=r^2π+rsπ:
B=r^2π
B=V/h=124/12=10,3cm^2
r^2=B/π
r=√(B/π)=1,81 cm
S=√(r^2+h^2)=√(12^2+1.81^2)=√(144+3,28)=12,13 cm
P=r^2π+rSπ=3,28*3,14+1,81*12,13*3,14=10,29+68,93=79,22 cm^2