Mathematics

Problem

A toy is formed by joining a solid right circular cone of radius

r

and slant height

l

to the flat face of a solid hemisphere of the same radius. Which expression represents the total surface area of this toy? a)

2\pi r(l+r)

\pi r l + 2\pi r^{2}

\pi r l + 3\pi r^{2}

\pi r l + 4\pi r^{2}