Finding the Third Proportional to 8,215 and 12,747.50

Step by Step Solution

1. Step 1: Write the proportion equation
   8,215 : 12,747.50 = 12,747.50 : x
2. Step 2: Convert to fraction form
   8,215/12,747.50 = 12,747.50/x
3. Step 3: Cross multiply
   8,215x = 12,747.50 × 12,747.50
4. Step 4: Simplify right side
   8,215x = 162,498,756.25
5. Step 5: Solve for x
   x = 162,498,756.25/8,215
6. Step 6: Final answer
   x = 19,780.74