Finding the Fourth Proportional to 21,068.73, 31,578.80 and 7,912.71

Step by Step Solution

1. Step 1: Write the proportion equation
   21,068.73 : 31,578.80 = 7,912.71 : x
2. Step 2: Convert to fraction form
   21,068.73/31,578.80 = 7,912.71/x
3. Step 3: Cross multiply
   21,068.73x = 31,578.80 × 7,912.71
4. Step 4: Simplify right side
   21,068.73x = 249,873,846.98
5. Step 5: Solve for x
   x = 249,873,846.98/21,068.73
6. Step 6: Final answer
   x = 11,859.94