Finding the Fourth Proportional to 21,896.04, 30,205.71 and 12,939.21

Step by Step Solution

1. Step 1: Write the proportion equation
   21,896.04 : 30,205.71 = 12,939.21 : x
2. Step 2: Convert to fraction form
   21,896.04/30,205.71 = 12,939.21/x
3. Step 3: Cross multiply
   21,896.04x = 30,205.71 × 12,939.21
4. Step 4: Simplify right side
   21,896.04x = 390,838,024.89
5. Step 5: Solve for x
   x = 390,838,024.89/21,896.04
6. Step 6: Final answer
   x = 17,849.71