Finding the Fourth Proportional to 21,128.64, 29,158.38 and 11,697.27

Step by Step Solution

1. Step 1: Write the proportion equation
   21,128.64 : 29,158.38 = 11,697.27 : x
2. Step 2: Convert to fraction form
   21,128.64/29,158.38 = 11,697.27/x
3. Step 3: Cross multiply
   21,128.64x = 29,158.38 × 11,697.27
4. Step 4: Simplify right side
   21,128.64x = 341,073,443.62
5. Step 5: Solve for x
   x = 341,073,443.62/21,128.64
6. Step 6: Final answer
   x = 16,142.71