Consider a regular pyramid were P is the perimeter of the base S in the slant height BA is a base area and LA is a the lateral area what is a valid formula for the surface area?

The surface area ( A ) of a regular pyramid can be calculated using the formula:

[ A = BA + LA ]

where ( BA ) is the area of the base and ( LA ) is the lateral area, which can be determined using the formula ( LA = \frac{1}{2} P \cdot l ), with ( P ) being the perimeter of the base and ( l ) the slant height. Thus, the complete surface area formula is:

[ A = BA + \frac{1}{2} P \cdot l ]