Finding the Fourth Proportional to 20,722.50, 31,114.89 and 12,439.58

Step by Step Solution

1. Step 1: Write the proportion equation
   20,722.50 : 31,114.89 = 12,439.58 : x
2. Step 2: Convert to fraction form
   20,722.50/31,114.89 = 12,439.58/x
3. Step 3: Cross multiply
   20,722.50x = 31,114.89 × 12,439.58
4. Step 4: Simplify right side
   20,722.50x = 387,056,007.77
5. Step 5: Solve for x
   x = 387,056,007.77/20,722.50
6. Step 6: Final answer
   x = 18,678.06