Finding the Fourth Proportional to 5,385.72, 7,429.78 and 3,147.68

Step by Step Solution

1. Step 1: Write the proportion equation
   5,385.72 : 7,429.78 = 3,147.68 : x
2. Step 2: Convert to fraction form
   5,385.72/7,429.78 = 3,147.68/x
3. Step 3: Cross multiply
   5,385.72x = 7,429.78 × 3,147.68
4. Step 4: Simplify right side
   5,385.72x = 23,386,569.91
5. Step 5: Solve for x
   x = 23,386,569.91/5,385.72
6. Step 6: Final answer
   x = 4,342.33