Finding the Fourth Proportional to 23,133.49, 31,978.02 and 20,640.31

Step by Step Solution

1. Step 1: Write the proportion equation
   23,133.49 : 31,978.02 = 20,640.31 : x
2. Step 2: Convert to fraction form
   23,133.49/31,978.02 = 20,640.31/x
3. Step 3: Cross multiply
   23,133.49x = 31,978.02 × 20,640.31
4. Step 4: Simplify right side
   23,133.49x = 660,036,285.96
5. Step 5: Solve for x
   x = 660,036,285.96/23,133.49
6. Step 6: Final answer
   x = 28,531.63