Finding the Third Proportional to 5,215,698 and 7,978,599

Step by Step Solution

1. Step 1: Write the proportion equation
   5,215,698 : 7,978,599 = 7,978,599 : x
2. Step 2: Convert to fraction form
   5,215,698/7,978,599 = 7,978,599/x
3. Step 3: Cross multiply
   5,215,698x = 7,978,599 × 7,978,599
4. Step 4: Simplify right side
   5,215,698x = 63,658,042,002,801
5. Step 5: Solve for x
   x = 63,658,042,002,801/5,215,698
6. Step 6: Final answer
   x = 12,205,085.88