Finding the Fourth Proportional to 1,123.56, 1,685.46 and 430.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.56 : 1,685.46 = 430.82 : x
2. Step 2: Convert to fraction form
   1,123.56/1,685.46 = 430.82/x
3. Step 3: Cross multiply
   1,123.56x = 1,685.46 × 430.82
4. Step 4: Simplify right side
   1,123.56x = 726,119.30
5. Step 5: Solve for x
   x = 726,119.30/1,123.56
6. Step 6: Final answer
   x = 646.27