We have a rectangular prism and we are given the following information.
![\begin{gathered} A=3m^3 \\ L=30\operatorname{cm} \\ W=40\operatorname{cm} \end{gathered}]()
We are asked to find the height of the rectangular prism
The very first thing to notice is that the given area and the given length, width has different units.
It is very important to have the same unit throughout otherwise there is a chance of making a mistake!
So let us first convert the given area from m into cm.
We know that 1 meter is equal to 100 centimeters.
![A=3\cdot100=300\operatorname{cm}]()
Now we can proceed to find the height of the prism.
Recall that the area of a rectangular prism is given by
Where W is the width, L is the length and H is the height of the rectangular prism.
Finally, just substitute the given values into the above equation and solve for H.
![\begin{gathered} 300=40\cdot30\cdot H \\ H=(300)/(40\cdot30) \\ H=(300)/(1200) \\ H=(1)/(4) \\ H=0.25\operatorname{cm} \end{gathered}]()
Therefore, the height of the rectangular prism is 0.25 cm.
The correct option is the last one 0.25 cm.