Finding the Fourth Proportional to 21,036.78, 29,031.42 and 12,086.10

Step by Step Solution

1. Step 1: Write the proportion equation
   21,036.78 : 29,031.42 = 12,086.10 : x
2. Step 2: Convert to fraction form
   21,036.78/29,031.42 = 12,086.10/x
3. Step 3: Cross multiply
   21,036.78x = 29,031.42 × 12,086.10
4. Step 4: Simplify right side
   21,036.78x = 350,876,645.26
5. Step 5: Solve for x
   x = 350,876,645.26/21,036.78
6. Step 6: Final answer
   x = 16,679.20