Finding the Fourth Proportional to 3,123.10, 4,385.30 and 3,123.10

Step by Step Solution

1. Step 1: Write the proportion equation
   3,123.10 : 4,385.30 = 3,123.10 : x
2. Step 2: Convert to fraction form
   3,123.10/4,385.30 = 3,123.10/x
3. Step 3: Cross multiply
   3,123.10x = 4,385.30 × 3,123.10
4. Step 4: Simplify right side
   3,123.10x = 13,695,730.43
5. Step 5: Solve for x
   x = 13,695,730.43/3,123.10
6. Step 6: Final answer
   x = 4,385.30