Volume of a tetrahedron calculator

Our program below will calculate the volume in litres of a Tetrahedron
Step 1: Measure the three sides of the base triangle in metres.
These are notated below as side a, side b and side c.
Step 2: Input the measurements of side a, b and c in the fields below as metres, ie 1.2 metres
Step 3: Measure the height of the top of the tetrahedron from the base in metres,
ensure that you are not measuring the length of one of the sides,
it must be the height from apex of the top, to  the tetrahedrons base.
This may take a few people to do!
Step 4: Just enter the height (h) of the tetrahedron in metres also.
Press the Calculate Volume button and you will get the volume.
Remember 1 litre of water weighs 1 kilogram, so this also is the weight of the payload.