Finding the Fourth Proportional to 21,123, 29,123.22 and 13,555.98

Step by Step Solution

1. Step 1: Write the proportion equation
   21,123 : 29,123.22 = 13,555.98 : x
2. Step 2: Convert to fraction form
   21,123/29,123.22 = 13,555.98/x
3. Step 3: Cross multiply
   21,123x = 29,123.22 × 13,555.98
4. Step 4: Simplify right side
   21,123x = 394,793,787.86
5. Step 5: Solve for x
   x = 394,793,787.86/21,123
6. Step 6: Final answer
   x = 18,690.23