Finding the Fourth Proportional to 1,389.69, 1,930.86 and 1,372.23

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.69 : 1,930.86 = 1,372.23 : x
2. Step 2: Convert to fraction form
   1,389.69/1,930.86 = 1,372.23/x
3. Step 3: Cross multiply
   1,389.69x = 1,930.86 × 1,372.23
4. Step 4: Simplify right side
   1,389.69x = 2,649,584.02
5. Step 5: Solve for x
   x = 2,649,584.02/1,389.69
6. Step 6: Final answer
   x = 1,906.60