Finding the Third Proportional to 12,399 and 20,830.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,399 : 20,830.50 = 20,830.50 : x
2. Step 2: Convert to fraction form
   12,399/20,830.50 = 20,830.50/x
3. Step 3: Cross multiply
   12,399x = 20,830.50 × 20,830.50
4. Step 4: Simplify right side
   12,399x = 433,909,730.25
5. Step 5: Solve for x
   x = 433,909,730.25/12,399
6. Step 6: Final answer
   x = 34,995.54