Finding the Fourth Proportional to 15,863.59, 21,890.55 and 8,789.86

Step by Step Solution

1. Step 1: Write the proportion equation
   15,863.59 : 21,890.55 = 8,789.86 : x
2. Step 2: Convert to fraction form
   15,863.59/21,890.55 = 8,789.86/x
3. Step 3: Cross multiply
   15,863.59x = 21,890.55 × 8,789.86
4. Step 4: Simplify right side
   15,863.59x = 192,414,869.82
5. Step 5: Solve for x
   x = 192,414,869.82/15,863.59
6. Step 6: Final answer
   x = 12,129.34