Finding the Fourth Proportional to 12,315.86, 18,490.89 and 8,558.78

Step by Step Solution

1. Step 1: Write the proportion equation
   12,315.86 : 18,490.89 = 8,558.78 : x
2. Step 2: Convert to fraction form
   12,315.86/18,490.89 = 8,558.78/x
3. Step 3: Cross multiply
   12,315.86x = 18,490.89 × 8,558.78
4. Step 4: Simplify right side
   12,315.86x = 158,259,505.74
5. Step 5: Solve for x
   x = 158,259,505.74/12,315.86
6. Step 6: Final answer
   x = 12,850.06