Finding the Fourth Proportional to 21,983.72, 30,339.02 and 12,420.29

Step by Step Solution

1. Step 1: Write the proportion equation
   21,983.72 : 30,339.02 = 12,420.29 : x
2. Step 2: Convert to fraction form
   21,983.72/30,339.02 = 12,420.29/x
3. Step 3: Cross multiply
   21,983.72x = 30,339.02 × 12,420.29
4. Step 4: Simplify right side
   21,983.72x = 376,819,426.72
5. Step 5: Solve for x
   x = 376,819,426.72/21,983.72
6. Step 6: Final answer
   x = 17,140.84