Finding the Third Proportional to 9,800 and 21,000

Step by Step Solution

1. Step 1: Write the proportion equation
   9,800 : 21,000 = 21,000 : x
2. Step 2: Convert to fraction form
   9,800/21,000 = 21,000/x
3. Step 3: Cross multiply
   9,800x = 21,000 × 21,000
4. Step 4: Simplify right side
   9,800x = 441,000,000
5. Step 5: Solve for x
   x = 441,000,000/9,800
6. Step 6: Final answer
   x = 45,000