Finding the Fourth Proportional to 21,210.31, 31,801.43 and 10,118.71

Step by Step Solution

1. Step 1: Write the proportion equation
   21,210.31 : 31,801.43 = 10,118.71 : x
2. Step 2: Convert to fraction form
   21,210.31/31,801.43 = 10,118.71/x
3. Step 3: Cross multiply
   21,210.31x = 31,801.43 × 10,118.71
4. Step 4: Simplify right side
   21,210.31x = 321,789,501.96
5. Step 5: Solve for x
   x = 321,789,501.96/21,210.31
6. Step 6: Final answer
   x = 15,171.37