Finding the Fourth Proportional to 22,478.20, 31,019.32 and 12,406.40

Step by Step Solution

1. Step 1: Write the proportion equation
   22,478.20 : 31,019.32 = 12,406.40 : x
2. Step 2: Convert to fraction form
   22,478.20/31,019.32 = 12,406.40/x
3. Step 3: Cross multiply
   22,478.20x = 31,019.32 × 12,406.40
4. Step 4: Simplify right side
   22,478.20x = 384,838,091.65
5. Step 5: Solve for x
   x = 384,838,091.65/22,478.20
6. Step 6: Final answer
   x = 17,120.50