Finding the Fourth Proportional to 21,106.24, 29,128.06 and 12,156.10

Step by Step Solution

1. Step 1: Write the proportion equation
   21,106.24 : 29,128.06 = 12,156.10 : x
2. Step 2: Convert to fraction form
   21,106.24/29,128.06 = 12,156.10/x
3. Step 3: Cross multiply
   21,106.24x = 29,128.06 × 12,156.10
4. Step 4: Simplify right side
   21,106.24x = 354,083,610.17
5. Step 5: Solve for x
   x = 354,083,610.17/21,106.24
6. Step 6: Final answer
   x = 16,776.25