12,4:3,2

31:8

Reason (assuming 12,4:3,2 means 12.4 to 3.2):

• Remove decimals: 124 : 32
• gcd(124,32) = 4
• divide: (124/4) : (32/4) = 31 : 8

So the simplified ratio is 31:8 (which is 3.875:1). If you intended something else, tell me and I’ll adjust.