Finding the Fourth Proportional to 21,251.40, 31,875.86 and 8,105.10

Step by Step Solution

1. Step 1: Write the proportion equation
   21,251.40 : 31,875.86 = 8,105.10 : x
2. Step 2: Convert to fraction form
   21,251.40/31,875.86 = 8,105.10/x
3. Step 3: Cross multiply
   21,251.40x = 31,875.86 × 8,105.10
4. Step 4: Simplify right side
   21,251.40x = 258,357,032.89
5. Step 5: Solve for x
   x = 258,357,032.89/21,251.40
6. Step 6: Final answer
   x = 12,157.18