Verified Answer :

If volume of cube           =  18 cm³
then each side of cube  =   ∛18cm³
                                      ≈  2.6207

Volume of squared pyramid  =  \(\frac{l ^{2} h }{3}\)
    since the pyramid fits perfectly in the cube then that means that
    there lengths and height are equal thus l² h =  18 cm³

∴   volume of pyramid  =  18 cm³  ÷  3
                                     =  6 cm

Thus B


View image JoshEast

To find the volume of the pyramid, divide the volume of the cube by 3. So that would be 18/3. The answer would be 6cm. Thank you for posting your question. I hope this answer helped you. Let me know if you need more help.