Finding the Fourth Proportional to 1,047.42, 1,571.55 and 431.43

Step by Step Solution

1. Step 1: Write the proportion equation
   1,047.42 : 1,571.55 = 431.43 : x
2. Step 2: Convert to fraction form
   1,047.42/1,571.55 = 431.43/x
3. Step 3: Cross multiply
   1,047.42x = 1,571.55 × 431.43
4. Step 4: Simplify right side
   1,047.42x = 678,013.82
5. Step 5: Solve for x
   x = 678,013.82/1,047.42
6. Step 6: Final answer
   x = 647.32