The formula for the volume of pyramids and cones tells you how much space is inside each object.
For these two solid shapes, the volume formula is the same: it's one third of the area of the base times the height.
Why? Here it is in a nutshell. The volume of three pyramids is equal to the volume of one prism with the same base and height. Similarly, the volume of three cones is equal to the volume of one cylinder with the same circular base and height.
The volume of each cone is equal to ⅓Bh = ⅓(28.3 × 10) = 94 ⅓ cm3. All three cones combined equals 283 cm3. The volume of the cylinder is equal to Bh = 28.3 × 10 = 283 cm3, ta da!
The volume of each pyramid is equal to ⅓Bh = ⅓(18 × 8) = 48 cm3. All three pyramids combined equals 144 cm3. The volume of the prism is equal to Bh = 18 × 8 = 144 cm3.