Finding the Fourth Proportional to 21,105.56, 29,123.15 and 12,155.97

Step by Step Solution

1. Step 1: Write the proportion equation
   21,105.56 : 29,123.15 = 12,155.97 : x
2. Step 2: Convert to fraction form
   21,105.56/29,123.15 = 12,155.97/x
3. Step 3: Cross multiply
   21,105.56x = 29,123.15 × 12,155.97
4. Step 4: Simplify right side
   21,105.56x = 354,020,186.14
5. Step 5: Solve for x
   x = 354,020,186.14/21,105.56
6. Step 6: Final answer
   x = 16,773.79