Finding the Third Proportional to 12,399.50 and 18,890.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,399.50 : 18,890.50 = 18,890.50 : x
2. Step 2: Convert to fraction form
   12,399.50/18,890.50 = 18,890.50/x
3. Step 3: Cross multiply
   12,399.50x = 18,890.50 × 18,890.50
4. Step 4: Simplify right side
   12,399.50x = 356,850,990.25
5. Step 5: Solve for x
   x = 356,850,990.25/12,399.50
6. Step 6: Final answer
   x = 28,779.47