Okay. So we know that the bar edge length is 8 cm (6+2) and the height is 6 cm....
And a pyramid's volume is 1/3 of a prism's volume.
If the base is square and both sides are 6 cm, the area is 36 cm^2. Then you multiply that area by the height: 288 cm^3.
BUT you have divide that by 3, because a pyramid's volume is 1/3 of a prism's volume: 288/3= 96 cm^3.
Answer: 96 cm^3