Finding the Third Proportional to 9,864 and 12,811.50

Step by Step Solution

1. Step 1: Write the proportion equation
   9,864 : 12,811.50 = 12,811.50 : x
2. Step 2: Convert to fraction form
   9,864/12,811.50 = 12,811.50/x
3. Step 3: Cross multiply
   9,864x = 12,811.50 × 12,811.50
4. Step 4: Simplify right side
   9,864x = 164,134,532.25
5. Step 5: Solve for x
   x = 164,134,532.25/9,864
6. Step 6: Final answer
   x = 16,639.75