Finding the Fourth Proportional to 15,431.21, 21,294.39 and 8,716.82

Step by Step Solution

1. Step 1: Write the proportion equation
   15,431.21 : 21,294.39 = 8,716.82 : x
2. Step 2: Convert to fraction form
   15,431.21/21,294.39 = 8,716.82/x
3. Step 3: Cross multiply
   15,431.21x = 21,294.39 × 8,716.82
4. Step 4: Simplify right side
   15,431.21x = 185,619,290.86
5. Step 5: Solve for x
   x = 185,619,290.86/15,431.21
6. Step 6: Final answer
   x = 12,028.82