Finding the Fourth Proportional to 21,897.54, 30,207.78 and 12,940.71

Step by Step Solution

1. Step 1: Write the proportion equation
   21,897.54 : 30,207.78 = 12,940.71 : x
2. Step 2: Convert to fraction form
   21,897.54/30,207.78 = 12,940.71/x
3. Step 3: Cross multiply
   21,897.54x = 30,207.78 × 12,940.71
4. Step 4: Simplify right side
   21,897.54x = 390,910,120.72
5. Step 5: Solve for x
   x = 390,910,120.72/21,897.54
6. Step 6: Final answer
   x = 17,851.78