Finding the Third Proportional to 139,920.50 and 221,915.50

Step by Step Solution

1. Step 1: Write the proportion equation
   139,920.50 : 221,915.50 = 221,915.50 : x
2. Step 2: Convert to fraction form
   139,920.50/221,915.50 = 221,915.50/x
3. Step 3: Cross multiply
   139,920.50x = 221,915.50 × 221,915.50
4. Step 4: Simplify right side
   139,920.50x = 49,246,489,140.25
5. Step 5: Solve for x
   x = 49,246,489,140.25/139,920.50
6. Step 6: Final answer
   x = 351,960.50