Finding the Third Proportional to 8,421 and 12,766.50

Step by Step Solution

1. Step 1: Write the proportion equation
   8,421 : 12,766.50 = 12,766.50 : x
2. Step 2: Convert to fraction form
   8,421/12,766.50 = 12,766.50/x
3. Step 3: Cross multiply
   8,421x = 12,766.50 × 12,766.50
4. Step 4: Simplify right side
   8,421x = 162,983,522.25
5. Step 5: Solve for x
   x = 162,983,522.25/8,421
6. Step 6: Final answer
   x = 19,354.41