Sorry Sir, i don't have the measurement of the flower diameter.
I was going through the book, 'Plant Groups' just a while ago for the keys to Sida & Abutilon genera and found nothing that can help me identify one from the other.
However, i should had been more careful on the leaf shape - it is Abutilon not Sida. Besides, flower stalks need to be more elongated to be a Sida cordata.
Thank you & Regards,
Surajit