To determine who is correct regarding the dimensions for calculating the surface area of the cone, we need to clarify the different dimensions involved in the calculation.
The surface area \( A \) of a cone is calculated using the formula:
\[ A = \pi r(r + l) \]
where:
- \( r \) is the radius of the base of the cone,
- \( l \) is the slant height of the cone.
From your information, it looks like:
- 8 in. is the height of the cone,
- 9 in. is the slant height of the cone,
- It seems to imply that the diameter is 7 in., which means the radius \( r = \frac{7}{2} = 3.5 \) in.
Based on the options given:
- If Claire is using 8 in. as the height, it is indeed the height and not necessary for calculating surface area directly.
- If Miles is using 9 in. as the slant height, then he is correct in that context for calculating the surface area.
So, the correct statement would be: Miles is correct because 9 in. is the slant height of the cone.