What is the volume of the right rectangular prism?

enter your answer in the box __mm^3

The   "1800" .

The volume is:   " 1800 mm³ " .

Explanation:  Volume = L * w * h = length * width* height ; 

We plug in the given values;  all of which are in units of "m" (meters);

Volume = (3 m) (1.5 m) (0.4 m)  =  1.8 m³ .

The question asks for the value, "the volume",  in units of:  " mm³ " ;  
                                                           that is, units of: "cubic millimeters" ;

So; we convert our obtained volume;  "1.8 m³ " ; to units of "mm³ ".

   Note the exact conversion:  1000 mm³ = 1 m³  ;

So;   V =  "1.8 m³ = {1.8 m³ * (1000 mm³/1 m³) }  =  (1.8 m³ * 1000) mm³ ;
                                                               
                                                                  V   =  1800 mm³ .

21, i'm pretty sure it's right lol