Formula of the Surface Area of a Regular Pyramid:
The surface area S of a regular pyramid with lateral area L and base area B is
S = L + B
By replacing L with one-half times the product of the slant height l and the
perimeter P of the base of the prism, the formula can also be written as
[tex]S= \frac{1}{2} lP+B[/tex]
[tex] \frac{1}{2} 2.24(12)+(3)^{2} [/tex]
Substitute and your answer is 22.44 cm³