Finding the Fourth Proportional to 858,128.83, 1,287,151.41 and 318,490.15

Step by Step Solution

1. Step 1: Write the proportion equation
   858,128.83 : 1,287,151.41 = 318,490.15 : x
2. Step 2: Convert to fraction form
   858,128.83/1,287,151.41 = 318,490.15/x
3. Step 3: Cross multiply
   858,128.83x = 1,287,151.41 × 318,490.15
4. Step 4: Simplify right side
   858,128.83x = 409,945,047,862.09
5. Step 5: Solve for x
   x = 409,945,047,862.09/858,128.83
6. Step 6: Final answer
   x = 477,719.70