Finding the Fourth Proportional to 8,139.60, 10,997.10 and 8,139.60

Step by Step Solution

1. Step 1: Write the proportion equation
   8,139.60 : 10,997.10 = 8,139.60 : x
2. Step 2: Convert to fraction form
   8,139.60/10,997.10 = 8,139.60/x
3. Step 3: Cross multiply
   8,139.60x = 10,997.10 × 8,139.60
4. Step 4: Simplify right side
   8,139.60x = 89,511,995.16
5. Step 5: Solve for x
   x = 89,511,995.16/8,139.60
6. Step 6: Final answer
   x = 10,997.10