please help me steps by steps

Answer:
question 19 = no solution because not enough information
question 20 = 18 for volume
Step-by-step explanation:
question 19:
cylinder formula
surface A =2πrh+2πr2
2π times 9 times 7 + 2π times 9 times 2
SA = 508.938009882
volume equals 395.840674352
question 20:
biggest one,
4h﹣a4+2(ab)2+2(ac)2﹣b4+2(bc)2﹣c4
V=18 IS the volume
Answer:
The last formulas are called
square based pyramid formula
cone formula
sphere formula
Can help with the first two as im short of time
Hope this helps.
Always remember to check the units^3
Step-by-step explanation:
19) V = π r 2 h = 1781.28303 ft3 = 1781.3ft^3
20) V = 1/2 b h l = 180m^3