The formula that shows the relation between LCM and HCF of a and b is: LCM (a, b) = (a × b) / HCF (a, b)
One number is a = 725
HCF (725, b) is 145, and LCM (725, b) = 2175
LCM (725, b) = (725 × b) / HCF (725, b)
2175 = (725 × b) / 145
725 × b = 2175 × 145
b = 315375/725
= 435
Therefore, the other number is 435.