Finding the Third Proportional to 315.50 and 677.50

Step by Step Solution

1. Step 1: Write the proportion equation
   315.50 : 677.50 = 677.50 : x
2. Step 2: Convert to fraction form
   315.50/677.50 = 677.50/x
3. Step 3: Cross multiply
   315.50x = 677.50 × 677.50
4. Step 4: Simplify right side
   315.50x = 459,006.25
5. Step 5: Solve for x
   x = 459,006.25/315.50
6. Step 6: Final answer
   x = 1,454.85