Finding the Fourth Proportional to 1,389.48, 2,086.05 and 930.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.48 : 2,086.05 = 930.21 : x
2. Step 2: Convert to fraction form
   1,389.48/2,086.05 = 930.21/x
3. Step 3: Cross multiply
   1,389.48x = 2,086.05 × 930.21
4. Step 4: Simplify right side
   1,389.48x = 1,940,464.57
5. Step 5: Solve for x
   x = 1,940,464.57/1,389.48
6. Step 6: Final answer
   x = 1,396.54