Finding the Fourth Proportional to 20,881.30, 31,280.17 and 12,556.72

Step by Step Solution

1. Step 1: Write the proportion equation
   20,881.30 : 31,280.17 = 12,556.72 : x
2. Step 2: Convert to fraction form
   20,881.30/31,280.17 = 12,556.72/x
3. Step 3: Cross multiply
   20,881.30x = 31,280.17 × 12,556.72
4. Step 4: Simplify right side
   20,881.30x = 392,776,336.24
5. Step 5: Solve for x
   x = 392,776,336.24/20,881.30
6. Step 6: Final answer
   x = 18,809.96