Finding the Fourth Proportional to 21,865.55, 30,169.27 and 12,439.31

Step by Step Solution

1. Step 1: Write the proportion equation
   21,865.55 : 30,169.27 = 12,439.31 : x
2. Step 2: Convert to fraction form
   21,865.55/30,169.27 = 12,439.31/x
3. Step 3: Cross multiply
   21,865.55x = 30,169.27 × 12,439.31
4. Step 4: Simplify right side
   21,865.55x = 375,284,902.00
5. Step 5: Solve for x
   x = 375,284,902.00/21,865.55
6. Step 6: Final answer
   x = 17,163.30