Finding the Fourth Proportional to 23,129.31, 31,918.10 and 12,920.48

Step by Step Solution

1. Step 1: Write the proportion equation
   23,129.31 : 31,918.10 = 12,920.48 : x
2. Step 2: Convert to fraction form
   23,129.31/31,918.10 = 12,920.48/x
3. Step 3: Cross multiply
   23,129.31x = 31,918.10 × 12,920.48
4. Step 4: Simplify right side
   23,129.31x = 412,396,948.50
5. Step 5: Solve for x
   x = 412,396,948.50/23,129.31
6. Step 6: Final answer
   x = 17,830.06