Finding the Fourth Proportional to 6,447.57, 8,899.79 and 3,931.31

Step by Step Solution

1. Step 1: Write the proportion equation
   6,447.57 : 8,899.79 = 3,931.31 : x
2. Step 2: Convert to fraction form
   6,447.57/8,899.79 = 3,931.31/x
3. Step 3: Cross multiply
   6,447.57x = 8,899.79 × 3,931.31
4. Step 4: Simplify right side
   6,447.57x = 34,987,769.27
5. Step 5: Solve for x
   x = 34,987,769.27/6,447.57
6. Step 6: Final answer
   x = 5,426.50