Finding the Third Proportional to 9,990 and 21,618

Step by Step Solution

1. Step 1: Write the proportion equation
   9,990 : 21,618 = 21,618 : x
2. Step 2: Convert to fraction form
   9,990/21,618 = 21,618/x
3. Step 3: Cross multiply
   9,990x = 21,618 × 21,618
4. Step 4: Simplify right side
   9,990x = 467,337,924
5. Step 5: Solve for x
   x = 467,337,924/9,990
6. Step 6: Final answer
   x = 46,780.57