Finding the Third Proportional to 396.50 and 503.50

Step by Step Solution

1. Step 1: Write the proportion equation
   396.50 : 503.50 = 503.50 : x
2. Step 2: Convert to fraction form
   396.50/503.50 = 503.50/x
3. Step 3: Cross multiply
   396.50x = 503.50 × 503.50
4. Step 4: Simplify right side
   396.50x = 253,512.25
5. Step 5: Solve for x
   x = 253,512.25/396.50
6. Step 6: Final answer
   x = 639.38