Finding the Fourth Proportional to 3,111.60, 4,369.20 and 3,111.60

Step by Step Solution

1. Step 1: Write the proportion equation
   3,111.60 : 4,369.20 = 3,111.60 : x
2. Step 2: Convert to fraction form
   3,111.60/4,369.20 = 3,111.60/x
3. Step 3: Cross multiply
   3,111.60x = 4,369.20 × 3,111.60
4. Step 4: Simplify right side
   3,111.60x = 13,595,202.72
5. Step 5: Solve for x
   x = 13,595,202.72/3,111.60
6. Step 6: Final answer
   x = 4,369.20