Question

Robert is making five cone shaped party hats for sisters birthday party from cardboard each party has a radius of 7 inches and a slant height of 4 inches how much cardboard does Robert need front to the nearest 10th

Answer 1

`439.5 in.^2`

Explanation:

The lateral area of a cone is given by the formula

`A=\pi r h'`

where

A is the lateral area

r is the radius of the cone

h' is the slant height of the cone

Here for the cone shaped party hats we have:

r = 7 in. is the radius of each cone

h' = 4 in. is the slant height

So the lateral area of each conic hat is

`A=\pi (7)(4)=87.9 in.^2`

However, here we have five hats in total; therefore, the total lateral area of the 5 hats is

`A'=5A=5(87.9)=439.5 in.^2`

So, the amount of cardboard that Robert needs to make the 5 conic hats is
`439.5 in.^2`.