using System;

public class Program

{

    public static void Main()

    {

        var StudyWeight = "0,1"; //study decimal must be typed in with comma, not dot

        var weightRange = Decimal.Parse(StudyWeight) * 10; //updated weight range

​

        decimal BaselineWeight = 36m;

        decimal weight = 39.7m;

        var result = Math.Round(Math.Abs(decimal.Divide(BaselineWeight - weight, BaselineWeight)), MidpointRounding.AwayFromZero); //current formula

        var result2 = Math.Ceiling(Math.Abs((BaselineWeight - weight) / BaselineWeight) * 100); //updated formula

        Console.WriteLine(result + " compared to " + result2 + " compared to " + weightRange);

    }

}