Finding the Fourth Proportional to 3,665.20, 5,124.80 and 3,665.20

Step by Step Solution

1. Step 1: Write the proportion equation
   3,665.20 : 5,124.80 = 3,665.20 : x
2. Step 2: Convert to fraction form
   3,665.20/5,124.80 = 3,665.20/x
3. Step 3: Cross multiply
   3,665.20x = 5,124.80 × 3,665.20
4. Step 4: Simplify right side
   3,665.20x = 18,783,416.96
5. Step 5: Solve for x
   x = 18,783,416.96/3,665.20
6. Step 6: Final answer
   x = 5,124.80