Finding the Third Proportional to 147.50 and 318.50

Step by Step Solution

1. Step 1: Write the proportion equation
   147.50 : 318.50 = 318.50 : x
2. Step 2: Convert to fraction form
   147.50/318.50 = 318.50/x
3. Step 3: Cross multiply
   147.50x = 318.50 × 318.50
4. Step 4: Simplify right side
   147.50x = 101,442.25
5. Step 5: Solve for x
   x = 101,442.25/147.50
6. Step 6: Final answer
   x = 687.74