Answer:
your answer would be 21
~hope this is the right answer, have a great day/night~
Step-by-step explanation:
-1 - (-7) = 6
5 - (-1) = 6
11 - 5 = 6
The common difference is 6.
If you add 6 to a term, you get the next term.

Volume Of A Cube = s^3 = (1/3)^3 = 1/27
There Are 8 Cubes In A Prism.
ThereFore, The Volume Of The Prism Is 8(1/27) = 8/27 Cubic Centimeters.
Hope This Helps!