Finding the Fourth Proportional to 21,609, 29,820.42 and 12,177.90

Step by Step Solution

1. Step 1: Write the proportion equation
   21,609 : 29,820.42 = 12,177.90 : x
2. Step 2: Convert to fraction form
   21,609/29,820.42 = 12,177.90/x
3. Step 3: Cross multiply
   21,609x = 29,820.42 × 12,177.90
4. Step 4: Simplify right side
   21,609x = 363,150,092.72
5. Step 5: Solve for x
   x = 363,150,092.72/21,609
6. Step 6: Final answer
   x = 16,805.50