Finding the Fourth Proportional to 21,111.38, 29,135.05 and 12,158.69

Step by Step Solution

1. Step 1: Write the proportion equation
   21,111.38 : 29,135.05 = 12,158.69 : x
2. Step 2: Convert to fraction form
   21,111.38/29,135.05 = 12,158.69/x
3. Step 3: Cross multiply
   21,111.38x = 29,135.05 × 12,158.69
4. Step 4: Simplify right side
   21,111.38x = 354,243,865.01
5. Step 5: Solve for x
   x = 354,243,865.01/21,111.38
6. Step 6: Final answer
   x = 16,779.76