Finding the Fourth Proportional to 10,891.60, 16,315.52 and 9,218.55

Step by Step Solution

1. Step 1: Write the proportion equation
   10,891.60 : 16,315.52 = 9,218.55 : x
2. Step 2: Convert to fraction form
   10,891.60/16,315.52 = 9,218.55/x
3. Step 3: Cross multiply
   10,891.60x = 16,315.52 × 9,218.55
4. Step 4: Simplify right side
   10,891.60x = 150,405,436.90
5. Step 5: Solve for x
   x = 150,405,436.90/10,891.60
6. Step 6: Final answer
   x = 13,809.31