Help with cross multiplication in excel

[Mohammed Attarwala]

Hi friends, 

i need a little help with creating a cross multiplication formula in excel. 

For example: 

Glasses     Kg

2                6

7                ?

This is the calculation i need to do. 

Also, i want to create a formula for when i just enter No. of glassses it will give me how much material i need to use. 

Please if someone can help me do it. 

Thank you

[#2]

Maybe you can try using a formula like this (See attached file for reference):

Ex 1: 

=A3*($B$2/$A$2)

Ex 2:

=A4*3

[#3]

=sumproduct()

[#4]

@Mohammed Attarwala 

you can use VBA

see the attached file

the function is called crossmult(a,b,c)

a   b 

c  crossmult(a,b,c)