Finding the Fourth Proportional to 21,661.71, 29,886.81 and 12,709.59

Step by Step Solution

1. Step 1: Write the proportion equation
   21,661.71 : 29,886.81 = 12,709.59 : x
2. Step 2: Convert to fraction form
   21,661.71/29,886.81 = 12,709.59/x
3. Step 3: Cross multiply
   21,661.71x = 29,886.81 × 12,709.59
4. Step 4: Simplify right side
   21,661.71x = 379,849,101.51
5. Step 5: Solve for x
   x = 379,849,101.51/21,661.71
6. Step 6: Final answer
   x = 17,535.51