Question

Which formulas can be used to find the surface of a regular pyramid with a square base where the perimeter of the base is equal to p s is the slant height, ba is the base area and la is the lateral area?

Answer 1

we have that
p---------> perimeter of the base
s---------> slant height
ba------> is the area of the base
la------> lateral area

we know that
[surface area of a regular pyramid]=area of the base+4*[area of one lateral triangle]

area of the base=ba
area of one lateral triangle=(p/4)*s/2----> p*s/8
[surface area of a regular pyramid]=ba+4*[p*s/8]----> ba+p*s/2

and

[surface area of a regular pyramid]=area of the base+lateral area
area of the base=ba
lateral area=la
so
[surface area of a regular pyramid]=ba+la

the answer is
surface area=ba+p*s/2
surface area=ba+la