Finding the Third Proportional to 8,539.88 and 12,390.75

Step by Step Solution

1. Step 1: Write the proportion equation
   8,539.88 : 12,390.75 = 12,390.75 : x
2. Step 2: Convert to fraction form
   8,539.88/12,390.75 = 12,390.75/x
3. Step 3: Cross multiply
   8,539.88x = 12,390.75 × 12,390.75
4. Step 4: Simplify right side
   8,539.88x = 153,530,685.56
5. Step 5: Solve for x
   x = 153,530,685.56/8,539.88
6. Step 6: Final answer
   x = 17,978.10