Finding the Fourth Proportional to 21,282.31, 31,890.35 and 8,127.50

Step by Step Solution

1. Step 1: Write the proportion equation
   21,282.31 : 31,890.35 = 8,127.50 : x
2. Step 2: Convert to fraction form
   21,282.31/31,890.35 = 8,127.50/x
3. Step 3: Cross multiply
   21,282.31x = 31,890.35 × 8,127.50
4. Step 4: Simplify right side
   21,282.31x = 259,188,919.67
5. Step 5: Solve for x
   x = 259,188,919.67/21,282.31
6. Step 6: Final answer
   x = 12,178.61