Finding the Third Proportional to 402.50 and 627.50

Step by Step Solution

1. Step 1: Write the proportion equation
   402.50 : 627.50 = 627.50 : x
2. Step 2: Convert to fraction form
   402.50/627.50 = 627.50/x
3. Step 3: Cross multiply
   402.50x = 627.50 × 627.50
4. Step 4: Simplify right side
   402.50x = 393,756.25
5. Step 5: Solve for x
   x = 393,756.25/402.50
6. Step 6: Final answer
   x = 978.28