Finding the Fourth Proportional to 21,040.61, 29,046.56 and 13,085.39

Step by Step Solution

1. Step 1: Write the proportion equation
   21,040.61 : 29,046.56 = 13,085.39 : x
2. Step 2: Convert to fraction form
   21,040.61/29,046.56 = 13,085.39/x
3. Step 3: Cross multiply
   21,040.61x = 29,046.56 × 13,085.39
4. Step 4: Simplify right side
   21,040.61x = 380,085,500.33
5. Step 5: Solve for x
   x = 380,085,500.33/21,040.61
6. Step 6: Final answer
   x = 18,064.38