Finding the Fourth Proportional to 21,061.62, 31,592.34 and 8,578.86

Step by Step Solution

1. Step 1: Write the proportion equation
   21,061.62 : 31,592.34 = 8,578.86 : x
2. Step 2: Convert to fraction form
   21,061.62/31,592.34 = 8,578.86/x
3. Step 3: Cross multiply
   21,061.62x = 31,592.34 × 8,578.86
4. Step 4: Simplify right side
   21,061.62x = 271,026,261.93
5. Step 5: Solve for x
   x = 271,026,261.93/21,061.62
6. Step 6: Final answer
   x = 12,868.25