Finding the Third Proportional to 31,686 and 67,242

Step by Step Solution

1. Step 1: Write the proportion equation
   31,686 : 67,242 = 67,242 : x
2. Step 2: Convert to fraction form
   31,686/67,242 = 67,242/x
3. Step 3: Cross multiply
   31,686x = 67,242 × 67,242
4. Step 4: Simplify right side
   31,686x = 4,521,486,564
5. Step 5: Solve for x
   x = 4,521,486,564/31,686
6. Step 6: Final answer
   x = 142,696.67