In the prism surface area formula Ph + 2B, B stands for what?

• A. Base area, the area of one base
• B. Base length
• C. Height
• D. Lateral side length

Answer: (A)

The question checks what the symbol B represents in the prism surface area formula SA = Ph + 2B. In a prism, the surface area is the sum of the lateral area and the areas of the two bases. The lateral area comes from the side rectangles, and its total is the base perimeter times the height, written as Ph. The two bases each contribute an area, so you add those together as 2B. That means B is the area of one base—the amount of space inside one of the polygonal faces at the ends. For example, if the base is a rectangle with sides a and b, then B = ab and the perimeter P = 2(a + b), so the total surface area is (2(a + b))h + 2ab. The other options describe lengths, not areas, so they don’t fit.