Formula of the surface area of a cone is:
S.A = Area of base + \(\frac{1}{2}\) × Perimeter of base × height of prism
S.A = \(\pi\)r² + \(\pi\)rl
= \(\pi\)(7)² + \(\pi\)(7)(18)
= 49\(\pi\) + 126\(\pi\)
= 175\(\pi\) in² (in terms of \(\pi\))
= 549.7787 in²
≈ 550 in²
