Finding the Third Proportional to 391.50 and 439.50

Step by Step Solution

1. Step 1: Write the proportion equation
   391.50 : 439.50 = 439.50 : x
2. Step 2: Convert to fraction form
   391.50/439.50 = 439.50/x
3. Step 3: Cross multiply
   391.50x = 439.50 × 439.50
4. Step 4: Simplify right side
   391.50x = 193,160.25
5. Step 5: Solve for x
   x = 193,160.25/391.50
6. Step 6: Final answer
   x = 493.39