Finding the Fourth Proportional to 15,721.86, 21,696.27 and 8,648.10

Step by Step Solution

1. Step 1: Write the proportion equation
   15,721.86 : 21,696.27 = 8,648.10 : x
2. Step 2: Convert to fraction form
   15,721.86/21,696.27 = 8,648.10/x
3. Step 3: Cross multiply
   15,721.86x = 21,696.27 × 8,648.10
4. Step 4: Simplify right side
   15,721.86x = 187,631,512.59
5. Step 5: Solve for x
   x = 187,631,512.59/15,721.86
6. Step 6: Final answer
   x = 11,934.43