Finding the Fourth Proportional to 21,279.31, 31,885.85 and 8,124.50

Step by Step Solution

1. Step 1: Write the proportion equation
   21,279.31 : 31,885.85 = 8,124.50 : x
2. Step 2: Convert to fraction form
   21,279.31/31,885.85 = 8,124.50/x
3. Step 3: Cross multiply
   21,279.31x = 31,885.85 × 8,124.50
4. Step 4: Simplify right side
   21,279.31x = 259,056,688.35
5. Step 5: Solve for x
   x = 259,056,688.35/21,279.31
6. Step 6: Final answer
   x = 12,174.11