I am certain there is a

[TheMacdonald]

I am certain there is a simpler way to calculate, but here’s what I did:

6×4= 24 square inches

http://www.onlineconversion.com/ to calculate the diameter of a circle with an area of 24 square inches.  5.54 inch diameter

Then used Paul’s calculator above to estimate 9 ounces of glass.

SOMEBODY else might check the math and theory.

TAM