Finding the Fourth Proportional to 12,219.72, 18,331.80 and 3,900.30

Step by Step Solution

1. Step 1: Write the proportion equation
   12,219.72 : 18,331.80 = 3,900.30 : x
2. Step 2: Convert to fraction form
   12,219.72/18,331.80 = 3,900.30/x
3. Step 3: Cross multiply
   12,219.72x = 18,331.80 × 3,900.30
4. Step 4: Simplify right side
   12,219.72x = 71,499,519.54
5. Step 5: Solve for x
   x = 71,499,519.54/12,219.72
6. Step 6: Final answer
   x = 5,851.16