Finding the Fourth Proportional to 20,770.31, 31,168.43 and 8,458.31

Step by Step Solution

1. Step 1: Write the proportion equation
   20,770.31 : 31,168.43 = 8,458.31 : x
2. Step 2: Convert to fraction form
   20,770.31/31,168.43 = 8,458.31/x
3. Step 3: Cross multiply
   20,770.31x = 31,168.43 × 8,458.31
4. Step 4: Simplify right side
   20,770.31x = 263,632,310.50
5. Step 5: Solve for x
   x = 263,632,310.50/20,770.31
6. Step 6: Final answer
   x = 12,692.75