Finding the Fourth Proportional to 1,048.54, 1,571.18 and 431.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,048.54 : 1,571.18 = 431.72 : x
2. Step 2: Convert to fraction form
   1,048.54/1,571.18 = 431.72/x
3. Step 3: Cross multiply
   1,048.54x = 1,571.18 × 431.72
4. Step 4: Simplify right side
   1,048.54x = 678,309.83
5. Step 5: Solve for x
   x = 678,309.83/1,048.54
6. Step 6: Final answer
   x = 646.91