Finding the Fourth Proportional to 12,139.74, 18,213.06 and 5,116.20

Step by Step Solution

1. Step 1: Write the proportion equation
   12,139.74 : 18,213.06 = 5,116.20 : x
2. Step 2: Convert to fraction form
   12,139.74/18,213.06 = 5,116.20/x
3. Step 3: Cross multiply
   12,139.74x = 18,213.06 × 5,116.20
4. Step 4: Simplify right side
   12,139.74x = 93,181,657.57
5. Step 5: Solve for x
   x = 93,181,657.57/12,139.74
6. Step 6: Final answer
   x = 7,675.75