Finding the Fourth Proportional to 9,864.80, 13,612.72 and 5,387.60

Step by Step Solution

1. Step 1: Write the proportion equation
   9,864.80 : 13,612.72 = 5,387.60 : x
2. Step 2: Convert to fraction form
   9,864.80/13,612.72 = 5,387.60/x
3. Step 3: Cross multiply
   9,864.80x = 13,612.72 × 5,387.60
4. Step 4: Simplify right side
   9,864.80x = 73,339,910.83
5. Step 5: Solve for x
   x = 73,339,910.83/9,864.80
6. Step 6: Final answer
   x = 7,434.50