Finding the Fourth Proportional to 21,057.59, 31,584.56 and 8,578.93

Step by Step Solution

1. Step 1: Write the proportion equation
   21,057.59 : 31,584.56 = 8,578.93 : x
2. Step 2: Convert to fraction form
   21,057.59/31,584.56 = 8,578.93/x
3. Step 3: Cross multiply
   21,057.59x = 31,584.56 × 8,578.93
4. Step 4: Simplify right side
   21,057.59x = 270,961,707.87
5. Step 5: Solve for x
   x = 270,961,707.87/21,057.59
6. Step 6: Final answer
   x = 12,867.65