Working out the height of a Cuboid

Hiya guys, im taking an early GCSE in november and i just need to clear a few things up.

How do i work out the height of a cuboid. The question is as follows:

Quote:

The Cuboid has a volume of 180cm3.

Calculate the height of the cuboid

Length = 8cm

Width = 5cm

I sort of thought that length x width but that would give you the area and i want the height , Or am i right?

Also another question i need help out is working out the volume.

Quote:

Use the approximations to estimate the volume of the cuboid.

Height = 9.89CM

Width = 20.3 CM

Length = 29.7CM

To approximations i would say

Height = 10CM

Width = 20CM

Length = 30CM

For volume is it x them all together?

10x20x30 ?

Thanks