250.55 cu. cm
Step-by-step explanation:
V=1/4h√﹣a^4+2(ab)^2+2(ac)^2﹣b4+2(bc)^2﹣c^4
=1/4x12x√-14^4+2·(14x14)^2+2·(14x3)^2﹣144+2·(14x3)^2﹣3^4
≈250.5494
mean, 40.6
step-by-step explanation: