Finding the Fourth Proportional to 428,433.18, 638,819.42 and 416,662.56

Step by Step Solution

1. Step 1: Write the proportion equation
   428,433.18 : 638,819.42 = 416,662.56 : x
2. Step 2: Convert to fraction form
   428,433.18/638,819.42 = 416,662.56/x
3. Step 3: Cross multiply
   428,433.18x = 638,819.42 × 416,662.56
4. Step 4: Simplify right side
   428,433.18x = 266,172,132,831.60
5. Step 5: Solve for x
   x = 266,172,132,831.60/428,433.18
6. Step 6: Final answer
   x = 621,268.72