I'm looking for a quick rework of this equation:
De = (1.3*(a*b)^0.625)/((a+b)^0.25)
where
de = equivalent diameter (mm, inches)
a = length of major or minor side (mm, inches)
b = length of minor or major side (mm, inches)
So that it can be solved for "a" if given "b" and "de".