Finding the Fourth Proportional to 402,699.03, 555,709.71 and 221,400.15

Step by Step Solution

1. Step 1: Write the proportion equation
   402,699.03 : 555,709.71 = 221,400.15 : x
2. Step 2: Convert to fraction form
   402,699.03/555,709.71 = 221,400.15/x
3. Step 3: Cross multiply
   402,699.03x = 555,709.71 × 221,400.15
4. Step 4: Simplify right side
   402,699.03x = 123,034,213,150.46
5. Step 5: Solve for x
   x = 123,034,213,150.46/402,699.03
6. Step 6: Final answer
   x = 305,523.99