Finding the Fourth Proportional to 21,021.59, 31,534.55 and 12,146.87

Step by Step Solution

1. Step 1: Write the proportion equation
   21,021.59 : 31,534.55 = 12,146.87 : x
2. Step 2: Convert to fraction form
   21,021.59/31,534.55 = 12,146.87/x
3. Step 3: Cross multiply
   21,021.59x = 31,534.55 × 12,146.87
4. Step 4: Simplify right side
   21,021.59x = 383,046,018.62
5. Step 5: Solve for x
   x = 383,046,018.62/21,021.59
6. Step 6: Final answer
   x = 18,221.55