Finding the Fourth Proportional to 321,199.40, 443,471.69 and 287,098.61

Step by Step Solution

1. Step 1: Write the proportion equation
   321,199.40 : 443,471.69 = 287,098.61 : x
2. Step 2: Convert to fraction form
   321,199.40/443,471.69 = 287,098.61/x
3. Step 3: Cross multiply
   321,199.40x = 443,471.69 × 287,098.61
4. Step 4: Simplify right side
   321,199.40x = 127,320,104,337.86
5. Step 5: Solve for x
   x = 127,320,104,337.86/321,199.40
6. Step 6: Final answer
   x = 396,389.61