Finding the Fourth Proportional to 428,517.72, 642,216.78 and 238,970.52

Step by Step Solution

1. Step 1: Write the proportion equation
   428,517.72 : 642,216.78 = 238,970.52 : x
2. Step 2: Convert to fraction form
   428,517.72/642,216.78 = 238,970.52/x
3. Step 3: Cross multiply
   428,517.72x = 642,216.78 × 238,970.52
4. Step 4: Simplify right side
   428,517.72x = 153,470,877,869.33
5. Step 5: Solve for x
   x = 153,470,877,869.33/428,517.72
6. Step 6: Final answer
   x = 358,143.60