Question

Find the surface area of a cone with a diameter of 13 and a slant height of 5. (use 3.14 for pi)

Answer 1

there are two formulas you have to combine (add). one is the area of the base of the cone which is a circle. area of a circle is \[\pi r ^{2}\]
area of the cone section is given as \[\pi rs\]
s is the length from top tip of the cone to the outer edge of circle, which is given in the problem as the slant height. so surface are is...
\[SA=\pi rs+\pi r ^{2}\]