Finding the Third Proportional to 9,900 and 21,015

Step by Step Solution

1. Step 1: Write the proportion equation
   9,900 : 21,015 = 21,015 : x
2. Step 2: Convert to fraction form
   9,900/21,015 = 21,015/x
3. Step 3: Cross multiply
   9,900x = 21,015 × 21,015
4. Step 4: Simplify right side
   9,900x = 441,630,225
5. Step 5: Solve for x
   x = 441,630,225/9,900
6. Step 6: Final answer
   x = 44,609.11