Final answer:
To calculate the surface area of a regular pyramid, add the area of the base to the combined area of the triangular faces. The base area is known, but without the base perimeter or side lengths, the total surface area cannot be determined.
Step-by-step explanation:
To find the surface area of a regular pyramid, we need to first know the surface area of the base, which is given as 84.3 cm². Then, we must calculate the surface area of the triangular faces. The student has provided the slant height (9 cm) and the base of the pyramid, but the length of the base side is not clear from the question. Typically, the formula for the surface area (SA) of a regular pyramid is SA = base area + 1/2 × perimeter of base × slant height. Since the area of the base is known, we only need the perimeter of the base to continue. If that perimeter or the number of sides and the length of each side were provided, we could use it to find the area of each triangle using the formula for the area of a triangle, which is 1/2 × base × height, and then multiply it by the number of triangles (sides) the pyramid has to get the total area of the triangular faces. This sum, along with the base area, would give us the total surface area of the pyramid. Without the individual side lengths or the perimeter, an exact surface area cannot be calculated.