Finding the Third Proportional to 139,286 and 212,391

Step by Step Solution

1. Step 1: Write the proportion equation
   139,286 : 212,391 = 212,391 : x
2. Step 2: Convert to fraction form
   139,286/212,391 = 212,391/x
3. Step 3: Cross multiply
   139,286x = 212,391 × 212,391
4. Step 4: Simplify right side
   139,286x = 45,109,936,881
5. Step 5: Solve for x
   x = 45,109,936,881/139,286
6. Step 6: Final answer
   x = 323,865.55