Finding the Fourth Proportional to 21,689.37, 29,921.40 and 12,736.71

Step by Step Solution

1. Step 1: Write the proportion equation
   21,689.37 : 29,921.40 = 12,736.71 : x
2. Step 2: Convert to fraction form
   21,689.37/29,921.40 = 12,736.71/x
3. Step 3: Cross multiply
   21,689.37x = 29,921.40 × 12,736.71
4. Step 4: Simplify right side
   21,689.37x = 381,100,194.59
5. Step 5: Solve for x
   x = 381,100,194.59/21,689.37
6. Step 6: Final answer
   x = 17,570.83