Finding the Fourth Proportional to 1,123.82, 1,686.02 and 430.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.82 : 1,686.02 = 430.55 : x
2. Step 2: Convert to fraction form
   1,123.82/1,686.02 = 430.55/x
3. Step 3: Cross multiply
   1,123.82x = 1,686.02 × 430.55
4. Step 4: Simplify right side
   1,123.82x = 725,921.49
5. Step 5: Solve for x
   x = 725,921.49/1,123.82
6. Step 6: Final answer
   x = 645.94