Finding the Third Proportional to 9,912 and 21,222

Step by Step Solution

1. Step 1: Write the proportion equation
   9,912 : 21,222 = 21,222 : x
2. Step 2: Convert to fraction form
   9,912/21,222 = 21,222/x
3. Step 3: Cross multiply
   9,912x = 21,222 × 21,222
4. Step 4: Simplify right side
   9,912x = 450,373,284
5. Step 5: Solve for x
   x = 450,373,284/9,912
6. Step 6: Final answer
   x = 45,437.18