Finding the Fourth Proportional to 429,870.27, 644,794.47 and 205,389.30

Step by Step Solution

1. Step 1: Write the proportion equation
   429,870.27 : 644,794.47 = 205,389.30 : x
2. Step 2: Convert to fraction form
   429,870.27/644,794.47 = 205,389.30/x
3. Step 3: Cross multiply
   429,870.27x = 644,794.47 × 205,389.30
4. Step 4: Simplify right side
   429,870.27x = 132,433,884,837.17
5. Step 5: Solve for x
   x = 132,433,884,837.17/429,870.27
6. Step 6: Final answer
   x = 308,078.73