Finding the Fourth Proportional to 1,123.47, 1,685.15 and 430.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.47 : 1,685.15 = 430.47 : x
2. Step 2: Convert to fraction form
   1,123.47/1,685.15 = 430.47/x
3. Step 3: Cross multiply
   1,123.47x = 1,685.15 × 430.47
4. Step 4: Simplify right side
   1,123.47x = 725,406.52
5. Step 5: Solve for x
   x = 725,406.52/1,123.47
6. Step 6: Final answer
   x = 645.68