Explanation
the volume of a cube is given by:
[tex]\text{Volume}_{cube}=side^3[/tex]Step 1
let
side= edge length= 20 cm
now, replace
[tex]\begin{gathered} \text{Volume}_{cube}=side^3 \\ \text{Volume}_{cube}=(20cm)^3 \\ \text{Volume}_{cube}=8000cm^3 \end{gathered}[/tex]I hope this helps you