Finding the Fourth Proportional to 21,321.48, 31,983.90 and 7,288.20

Step by Step Solution

1. Step 1: Write the proportion equation
   21,321.48 : 31,983.90 = 7,288.20 : x
2. Step 2: Convert to fraction form
   21,321.48/31,983.90 = 7,288.20/x
3. Step 3: Cross multiply
   21,321.48x = 31,983.90 × 7,288.20
4. Step 4: Simplify right side
   21,321.48x = 233,105,059.98
5. Step 5: Solve for x
   x = 233,105,059.98/21,321.48
6. Step 6: Final answer
   x = 10,932.87