Finding the Fourth Proportional to 10,958.69, 16,418.90 and 9,121.61

Step by Step Solution

1. Step 1: Write the proportion equation
   10,958.69 : 16,418.90 = 9,121.61 : x
2. Step 2: Convert to fraction form
   10,958.69/16,418.90 = 9,121.61/x
3. Step 3: Cross multiply
   10,958.69x = 16,418.90 × 9,121.61
4. Step 4: Simplify right side
   10,958.69x = 149,766,866.28
5. Step 5: Solve for x
   x = 149,766,866.28/10,958.69
6. Step 6: Final answer
   x = 13,666.49