Finding the Fourth Proportional to 21,559.50, 29,753.82 and 12,128.76

Step by Step Solution

1. Step 1: Write the proportion equation
   21,559.50 : 29,753.82 = 12,128.76 : x
2. Step 2: Convert to fraction form
   21,559.50/29,753.82 = 12,128.76/x
3. Step 3: Cross multiply
   21,559.50x = 29,753.82 × 12,128.76
4. Step 4: Simplify right side
   21,559.50x = 360,876,941.86
5. Step 5: Solve for x
   x = 360,876,941.86/21,559.50
6. Step 6: Final answer
   x = 16,738.65