Finding the Fourth Proportional to 22,470.72, 31,009.56 and 12,911.28

Step by Step Solution

1. Step 1: Write the proportion equation
   22,470.72 : 31,009.56 = 12,911.28 : x
2. Step 2: Convert to fraction form
   22,470.72/31,009.56 = 12,911.28/x
3. Step 3: Cross multiply
   22,470.72x = 31,009.56 × 12,911.28
4. Step 4: Simplify right side
   22,470.72x = 400,373,111.84
5. Step 5: Solve for x
   x = 400,373,111.84/22,470.72
6. Step 6: Final answer
   x = 17,817.55