Finding the Fourth Proportional to 21,301.40, 29,399 and 12,800.72

Step by Step Solution

1. Step 1: Write the proportion equation
   21,301.40 : 29,399 = 12,800.72 : x
2. Step 2: Convert to fraction form
   21,301.40/29,399 = 12,800.72/x
3. Step 3: Cross multiply
   21,301.40x = 29,399 × 12,800.72
4. Step 4: Simplify right side
   21,301.40x = 376,328,367.28
5. Step 5: Solve for x
   x = 376,328,367.28/21,301.40
6. Step 6: Final answer
   x = 17,666.84