Finding the Third Proportional to 8,431.50 and 13,399.50

Step by Step Solution

1. Step 1: Write the proportion equation
   8,431.50 : 13,399.50 = 13,399.50 : x
2. Step 2: Convert to fraction form
   8,431.50/13,399.50 = 13,399.50/x
3. Step 3: Cross multiply
   8,431.50x = 13,399.50 × 13,399.50
4. Step 4: Simplify right side
   8,431.50x = 179,546,600.25
5. Step 5: Solve for x
   x = 179,546,600.25/8,431.50
6. Step 6: Final answer
   x = 21,294.74