Finding the Third Proportional to 8,471.50 and 12,399.50

Step by Step Solution

1. Step 1: Write the proportion equation
   8,471.50 : 12,399.50 = 12,399.50 : x
2. Step 2: Convert to fraction form
   8,471.50/12,399.50 = 12,399.50/x
3. Step 3: Cross multiply
   8,471.50x = 12,399.50 × 12,399.50
4. Step 4: Simplify right side
   8,471.50x = 153,747,600.25
5. Step 5: Solve for x
   x = 153,747,600.25/8,471.50
6. Step 6: Final answer
   x = 18,148.80