Finding the Fourth Proportional to 21,109.50, 29,128.59 and 11,676.78

Step by Step Solution

1. Step 1: Write the proportion equation
   21,109.50 : 29,128.59 = 11,676.78 : x
2. Step 2: Convert to fraction form
   21,109.50/29,128.59 = 11,676.78/x
3. Step 3: Cross multiply
   21,109.50x = 29,128.59 × 11,676.78
4. Step 4: Simplify right side
   21,109.50x = 340,128,137.14
5. Step 5: Solve for x
   x = 340,128,137.14/21,109.50
6. Step 6: Final answer
   x = 16,112.56