Finding the Fourth Proportional to 12,833.52, 19,218.15 and 8,139.30

Step by Step Solution

1. Step 1: Write the proportion equation
   12,833.52 : 19,218.15 = 8,139.30 : x
2. Step 2: Convert to fraction form
   12,833.52/19,218.15 = 8,139.30/x
3. Step 3: Cross multiply
   12,833.52x = 19,218.15 × 8,139.30
4. Step 4: Simplify right side
   12,833.52x = 156,422,288.30
5. Step 5: Solve for x
   x = 156,422,288.30/12,833.52
6. Step 6: Final answer
   x = 12,188.57