Finding the Fourth Proportional to 1,123.91, 1,684.71 and 430.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.91 : 1,684.71 = 430.39 : x
2. Step 2: Convert to fraction form
   1,123.91/1,684.71 = 430.39/x
3. Step 3: Cross multiply
   1,123.91x = 1,684.71 × 430.39
4. Step 4: Simplify right side
   1,123.91x = 725,082.34
5. Step 5: Solve for x
   x = 725,082.34/1,123.91
6. Step 6: Final answer
   x = 645.14