Hi there!
Here we go:
The formula to find the volume is: Length × Width × Height = X units³
Length : 3.4
Width : 3.4
Height : 3.4
Replace the values in the formula and calculate everything :
3.4 × 3.4 × 3.4 = 39,304 units³
There you go! I really hope this helped, if there's anything just let me know! :)