Finding the Fourth Proportional to 12,013.01, 18,019.12 and 5,439.20

Step by Step Solution

1. Step 1: Write the proportion equation
   12,013.01 : 18,019.12 = 5,439.20 : x
2. Step 2: Convert to fraction form
   12,013.01/18,019.12 = 5,439.20/x
3. Step 3: Cross multiply
   12,013.01x = 18,019.12 × 5,439.20
4. Step 4: Simplify right side
   12,013.01x = 98,009,597.50
5. Step 5: Solve for x
   x = 98,009,597.50/12,013.01
6. Step 6: Final answer
   x = 8,158.62