Program Is Supposed To Operate On Decimals

My program is supposed to operate on decimals because it concerns volume of packagings. I learnt that what normally is simple arithmetic (100 cm × 75 cm × 60 cm = 0.45 m³) in Java gives only approximate value (something like 0.44(9) m³ in this case). That's close enough so I probably shouldn't worry, but the thing is that although for one packaging the difference is barely visible—if at all—for thousands of packagings it'll make a difference. It'll be worse when I get to counting money.

I found two solutions:
1) Using integers and so-called decorative decimal point on display. I have a bad feeling about this, though.
2) Using BigDecimal.

Now, BigDecimal seems like a nice solution. I tried it and so far it looks okay. But just look at an excerpt from my program that I had to re-write (previously it looked perfectly fine as a single line):

volume = dimensions
.get("Length").multiply(dimensions.get("Width")
.multiply(dimensions.get("Height")))
.divide(new BigDecimal("1000000"));

I'm using a HashMap to store dimensions. I figured it'd make it easy for me to manage and display data later on.