## Algebra 1: Common Core (15th Edition)

131.9 $cm^{2}$ No. Doubling the radius or the height does not double the surface area.
The general equation for the surface area of a cone is: $A= \pi r(h+r)$ We are given that the height is 11 cm and the radius is 3 cm. h= 11 r=3 We substitute the numbers for the variables in the equation. A= $\pi$(3)(11+3) A= 131.9 $cm^{2}$ ~~~ Surface area when doubling the radius: h= 11 r= 3 $\times$ 2 = 6 A= $\pi$(6)(11+6) A=320.28 $cm^{2}$ ** The surface area is more than double the initial surface area. ~~~ Surface area when doubling the height: h= 11 $\times$ 2 = 22 r= 3 A= $\pi$(3)(22+3) A=235.5 $cm^{2}$ ** The surface area is less than double the initial surface area.