Finding the Fourth Proportional to 28,112.67, 42,176.31 and 8,391.23

Step by Step Solution

1. Step 1: Write the proportion equation
   28,112.67 : 42,176.31 = 8,391.23 : x
2. Step 2: Convert to fraction form
   28,112.67/42,176.31 = 8,391.23/x
3. Step 3: Cross multiply
   28,112.67x = 42,176.31 × 8,391.23
4. Step 4: Simplify right side
   28,112.67x = 353,910,906.88
5. Step 5: Solve for x
   x = 353,910,906.88/28,112.67
6. Step 6: Final answer
   x = 12,589.02