What is the volume of this square pyramid? a 1,296cmb 1,620cmc 3,888cmd 11,664cm

a square pyramid with base edge length 18 cm and height 12 cm

its volume

The formula for the volume of a pyramid is

... V = (1/3)Bh . . . . . where B is the area of the base and h is the height

The formula for the area of a square is

... A = s² . . . . . . . . . where s is the length of the side.

For the given pyramid, the area of the base is

... A = (18 cm)² = 324 cm²

so the volume is

... V = (1/3)(324 cm²)(12 cm) = 1296 cm³ . . . . . matches selection A

so, converting firstly the mixed fractions to improper fractions and then "adding".