Finding the Fourth Proportional to 1,123.06, 1,684.71 and 430.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.06 : 1,684.71 = 430.31 : x
2. Step 2: Convert to fraction form
   1,123.06/1,684.71 = 430.31/x
3. Step 3: Cross multiply
   1,123.06x = 1,684.71 × 430.31
4. Step 4: Simplify right side
   1,123.06x = 724,949.65
5. Step 5: Solve for x
   x = 724,949.65/1,123.06
6. Step 6: Final answer
   x = 645.51