Finding the Fourth Proportional to 13,139.46, 18,120.65 and 8,422.83

Step by Step Solution

1. Step 1: Write the proportion equation
   13,139.46 : 18,120.65 = 8,422.83 : x
2. Step 2: Convert to fraction form
   13,139.46/18,120.65 = 8,422.83/x
3. Step 3: Cross multiply
   13,139.46x = 18,120.65 × 8,422.83
4. Step 4: Simplify right side
   13,139.46x = 152,627,112.33
5. Step 5: Solve for x
   x = 152,627,112.33/13,139.46
6. Step 6: Final answer
   x = 11,615.93