Finding the Fourth Proportional to 21,076.56, 29,083.05 and 13,121.37

Step by Step Solution

1. Step 1: Write the proportion equation
   21,076.56 : 29,083.05 = 13,121.37 : x
2. Step 2: Convert to fraction form
   21,076.56/29,083.05 = 13,121.37/x
3. Step 3: Cross multiply
   21,076.56x = 29,083.05 × 13,121.37
4. Step 4: Simplify right side
   21,076.56x = 381,609,459.78
5. Step 5: Solve for x
   x = 381,609,459.78/21,076.56
6. Step 6: Final answer
   x = 18,105.87