Question

Joyce, John and Jolynda were discussing their formulas for the total surface area of a cone.These are the their formulas. Select all the formulas that are correct.

Answer 1

The total surface area of a cone is expressed as

`\begin{gathered} Total\text{ surface area = curved surface area +area of circular base} \\ where \\ curved\text{ }surface\text{ }area\text{ = }\pi rl \\ area\text{ }of\text{ }circular\text{ }base\text{ = }\pi r^2 \\ \therefore \\ Total\text{ surface area=}\pi rl+\pi r^2 \\ =\pi r(l+r) \end{gathered}`

From the given options, the correct formulas are: