ashyantony is right!
if you are sure with the scales then u will not have doubt on chords.. as you know the formulas for a basic Major scale goes like 1 3 5 and goes like this.,
with that notes you mentioned sa re ga ga for eg: we'll take it for C major scale, you play the melody, find the apt scale, and using the formula u'll know the chord. for C major song u can add Aminor too and it sounds nice on same parts,. C Major's related Minor is Am. you play and you'll hear the difference ;-)
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