Finding the Third Proportional to 8,403 and 12,688.50

Step by Step Solution

1. Step 1: Write the proportion equation
   8,403 : 12,688.50 = 12,688.50 : x
2. Step 2: Convert to fraction form
   8,403/12,688.50 = 12,688.50/x
3. Step 3: Cross multiply
   8,403x = 12,688.50 × 12,688.50
4. Step 4: Simplify right side
   8,403x = 160,998,032.25
5. Step 5: Solve for x
   x = 160,998,032.25/8,403
6. Step 6: Final answer
   x = 19,159.59