Answer:
4.5
Explanation:
volume is length x breath x height
since 75 is in cm, we convert it to metre
= 0.75m
= 1.2m x 5m x 0.75m
=

The voltage across resistor is 75 volts, because you can solve this using the ohm law.
Hope this help!!
Do you have a book about it? or if you have a dictionary?