Finding the Fourth Proportional to 11,665.80, 16,099.11 and 7,129.22

Step by Step Solution

1. Step 1: Write the proportion equation
   11,665.80 : 16,099.11 = 7,129.22 : x
2. Step 2: Convert to fraction form
   11,665.80/16,099.11 = 7,129.22/x
3. Step 3: Cross multiply
   11,665.80x = 16,099.11 × 7,129.22
4. Step 4: Simplify right side
   11,665.80x = 114,774,016.50
5. Step 5: Solve for x
   x = 114,774,016.50/11,665.80
6. Step 6: Final answer
   x = 9,838.50