Finding the Third Proportional to 9,990 and 21,772

Step by Step Solution

1. Step 1: Write the proportion equation
   9,990 : 21,772 = 21,772 : x
2. Step 2: Convert to fraction form
   9,990/21,772 = 21,772/x
3. Step 3: Cross multiply
   9,990x = 21,772 × 21,772
4. Step 4: Simplify right side
   9,990x = 474,019,984
5. Step 5: Solve for x
   x = 474,019,984/9,990
6. Step 6: Final answer
   x = 47,449.45