Finding the Fourth Proportional to 21,292.72, 31,934.96 and 8,142

Step by Step Solution

1. Step 1: Write the proportion equation
   21,292.72 : 31,934.96 = 8,142 : x
2. Step 2: Convert to fraction form
   21,292.72/31,934.96 = 8,142/x
3. Step 3: Cross multiply
   21,292.72x = 31,934.96 × 8,142
4. Step 4: Simplify right side
   21,292.72x = 260,014,444.32
5. Step 5: Solve for x
   x = 260,014,444.32/21,292.72
6. Step 6: Final answer
   x = 12,211.42