Finding the Third Proportional to 8,418 and 12,505.50

Step by Step Solution

1. Step 1: Write the proportion equation
   8,418 : 12,505.50 = 12,505.50 : x
2. Step 2: Convert to fraction form
   8,418/12,505.50 = 12,505.50/x
3. Step 3: Cross multiply
   8,418x = 12,505.50 × 12,505.50
4. Step 4: Simplify right side
   8,418x = 156,387,530.25
5. Step 5: Solve for x
   x = 156,387,530.25/8,418
6. Step 6: Final answer
   x = 18,577.75