Finding the Fourth Proportional to 498,216.72, 746,758.72 and 438,128

Step by Step Solution

1. Step 1: Write the proportion equation
   498,216.72 : 746,758.72 = 438,128 : x
2. Step 2: Convert to fraction form
   498,216.72/746,758.72 = 438,128/x
3. Step 3: Cross multiply
   498,216.72x = 746,758.72 × 438,128
4. Step 4: Simplify right side
   498,216.72x = 327,175,904,476.16
5. Step 5: Solve for x
   x = 327,175,904,476.16/498,216.72
6. Step 6: Final answer
   x = 656,693.95