Finding the Fourth Proportional to 21,003.72, 31,511.42 and 9,158.53

Step by Step Solution

1. Step 1: Write the proportion equation
   21,003.72 : 31,511.42 = 9,158.53 : x
2. Step 2: Convert to fraction form
   21,003.72/31,511.42 = 9,158.53/x
3. Step 3: Cross multiply
   21,003.72x = 31,511.42 × 9,158.53
4. Step 4: Simplify right side
   21,003.72x = 288,598,285.41
5. Step 5: Solve for x
   x = 288,598,285.41/21,003.72
6. Step 6: Final answer
   x = 13,740.34