Finding the Third Proportional to 12,800 and 20,000

Step by Step Solution

1. Step 1: Write the proportion equation
   12,800 : 20,000 = 20,000 : x
2. Step 2: Convert to fraction form
   12,800/20,000 = 20,000/x
3. Step 3: Cross multiply
   12,800x = 20,000 × 20,000
4. Step 4: Simplify right side
   12,800x = 400,000,000
5. Step 5: Solve for x
   x = 400,000,000/12,800
6. Step 6: Final answer
   x = 31,250