The height of the red cone hr= 4cm. The height of the blue cone is hb= 8cm.

Question

If the surface area of the red cone is 115cm2 , what is the surface area of the blue cone in cm2?

Answer 1

The radius of the red cone is 3.876
If the radius of the blue cone is the same, then its surface is 155.420

If, however, the cones are similar, then since h is twice as big, the surface area will be 4 times as big: 460