Help! Please explain I have a test tomorrow !

base= 10 ft
height= 12 ft
the surface area of the given pyramid.
[tex]s.a = {a}^{2} + 2a \sqrt{ \frac{ {a}^{2} }{4} + {h}^{2} } [/tex]
[tex]s.a = {10}^{2} + 2 \times 10 \times \sqrt{ \frac{ {10}^{2} }{4} { \times 12}^{2} } [/tex]
[tex]s.a = 360 \: {ft}^{2} [/tex]
therefore, the surface area of the given pyramid is 360 square feets.
answer= option D