Finding the Fourth Proportional to 1,399.80, 2,100.29 and 1,389.27

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.80 : 2,100.29 = 1,389.27 : x
2. Step 2: Convert to fraction form
   1,399.80/2,100.29 = 1,389.27/x
3. Step 3: Cross multiply
   1,399.80x = 2,100.29 × 1,389.27
4. Step 4: Simplify right side
   1,399.80x = 2,917,862.94
5. Step 5: Solve for x
   x = 2,917,862.94/1,399.80
6. Step 6: Final answer
   x = 2,084.49