Finding the Fourth Proportional to 21,091.59, 29,111.40 and 12,708.09

Step by Step Solution

1. Step 1: Write the proportion equation
   21,091.59 : 29,111.40 = 12,708.09 : x
2. Step 2: Convert to fraction form
   21,091.59/29,111.40 = 12,708.09/x
3. Step 3: Cross multiply
   21,091.59x = 29,111.40 × 12,708.09
4. Step 4: Simplify right side
   21,091.59x = 369,950,291.23
5. Step 5: Solve for x
   x = 369,950,291.23/21,091.59
6. Step 6: Final answer
   x = 17,540.18