The surface area SA of the cone is the sum of the base area B and the lateral area LA. The lateral area is half the product of the circumference and the slant height. The radius is half the diameter, so is 4 inches.
SA = B + LA
= πr² + (1/2)(2πrh) . . . . where h is the slant height
= (πr)(r +h)
Filling in the numbers, you have ...
SA = (3.14)(4 in)(4 in + 7 in) = 3.14×(44 in²) = 138.16 in²
