In your question, there is a missing data: the slant height of the pyramid.
Indeed, the total surface area can be found adding the base surface plus the lateral surface. In order to find the lateral surface, you can use the formula:
LS = (slant height × perimeter) / 2
Therefore:
if your slant height is 28, your answer will be 4116cm²
if your slant height is 35, your answer will be 4704cm²
if your slant height is 348.5, your answer will be 31038cm²
if your slant height is 14, your answer will be 2940cm²
