Answer:
Part 1) The lateral area is [tex]LA=791.7\ ft^{2}[/tex]
Part 2) The surface area is [tex]SA=1,244.1\ ft^{2}[/tex]
[tex]LA=791.7\ ft^{2}[/tex], [tex]SA=1,244.1\ ft^{2}[/tex]
Step-by-step explanation:
step 1
Find the lateral area of the cone
we know that
The lateral area of the cone is equal to
[tex]LA=\pi rl[/tex]
we have
[tex]r=12\ ft[/tex]
[tex]l=21\ ft[/tex]
substitute
[tex]LA=(3.1416)(12)(21)=791.7\ ft^{2}[/tex]
step 2
Find the surface area of the cone
we know that
The surface area of the cone is equal to
[tex]SA=\pi r^{2}+LA[/tex]
we have
[tex]r=12\ ft[/tex]
[tex]LA=791.7\ ft^{2}[/tex]
substitute
[tex]SA=(3.1416)(12)^{2}+791.7=1,244.1\ ft^{2}[/tex]