I am certain there is a
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.