Multiply two cells based on information in two other cells

Hi
I am looking to get a formula for working out Metres of wire based on material type, diameter and weight
I have 2 cells where the information is validated from a list
The first is material type and the list contains things such as stainless, brass etc
The second is wire diameter and has a list from 1 to 5mm
On a separate page I have a list of materials weights and metres for example stainless 1mm diameter = 161 m per kg

I need a formula that checks what material is selected from the list, then checks what diameter is selected from the other drop down list. Based on this selection it looks up the number of m per kg for that material type and diameter from the list I have generated and then multiplies it by the figure in another cell which is order qty

The purpose of this is so that when I select a material then select a diameter and then enter an order qty in KG another cell is populated with the amount of metres I will end up with
So in theory material type and diameter determine the number of m per KG and then it auto multiplies it my order qty and displays in another cell

I have attached the sheet so you get a better understanding
I am selecting the diameter in D column, selecting material type in E column and entering an amount in KG in F column. On the second tab (m per kg chart) i need it to grab the associated figure (e.g. for 2 mm stainless the figure it should pick up is 40) and then i need this figure to multiply by the order qty in F column and display the final figure in G column


Please shout up if you need more information in order to be able to assist me

Many Thanks

Stanster