Claire says that in order to calculate the surface area of the cone, she needs to use 8 in. Miles says that in order to calculate the surface area of the cone, he needs to use 9 in. Who is correct and why? (1 point)

Question

Claire says that in order to calculate the surface area of the cone, she needs to use 8 in. Miles says that in order to calculate the surface area of the cone, he needs to use 9 in. Who is correct and why? (1 point)

Diameter= 7in
Height=8in
Slant height=9in

Responses Miles is correct because 9 in. is the height of the cone. Miles is correct because 9 in. is the height of the cone.
Claire is correct because 8 in. is the height of the cone. Claire is correct because 8 in. is the height of the cone.
Miles is correct because 9 in. is the slant height of the cone. Miles is correct because 9 in. is the slant height of the cone.
Claire is correct because 8 in. is the slant height of the cone.

Answer 1

Miles is correct because 9 in. is the slant height of the cone. The formula for calculating the surface area of a cone is A = πr(r + l), where r is the radius of the cone's base and l is the slant height. In this case, the diameter is 7 in, so the radius is 7/2 = 3.5 in. The slant height is given as 9 in. Plugging these values into the formula, we get A = π(3.5)(3.5 + 9) = π(3.5)(12.5) = 43.75π in^2. Therefore, Miles is correct in stating that the slant height of the cone is needed to calculate its surface area.