Finding the Third Proportional to 517.50 and 631.50

Step by Step Solution

1. Step 1: Write the proportion equation
   517.50 : 631.50 = 631.50 : x
2. Step 2: Convert to fraction form
   517.50/631.50 = 631.50/x
3. Step 3: Cross multiply
   517.50x = 631.50 × 631.50
4. Step 4: Simplify right side
   517.50x = 398,792.25
5. Step 5: Solve for x
   x = 398,792.25/517.50
6. Step 6: Final answer
   x = 770.61