Finding the Fourth Proportional to 15,715.41, 21,687.42 and 8,641.89

Step by Step Solution

1. Step 1: Write the proportion equation
   15,715.41 : 21,687.42 = 8,641.89 : x
2. Step 2: Convert to fraction form
   15,715.41/21,687.42 = 8,641.89/x
3. Step 3: Cross multiply
   15,715.41x = 21,687.42 × 8,641.89
4. Step 4: Simplify right side
   15,715.41x = 187,420,298.02
5. Step 5: Solve for x
   x = 187,420,298.02/15,715.41
6. Step 6: Final answer
   x = 11,925.89