Finding the Third Proportional to 402.50 and 802.50

Step by Step Solution

1. Step 1: Write the proportion equation
   402.50 : 802.50 = 802.50 : x
2. Step 2: Convert to fraction form
   402.50/802.50 = 802.50/x
3. Step 3: Cross multiply
   402.50x = 802.50 × 802.50
4. Step 4: Simplify right side
   402.50x = 644,006.25
5. Step 5: Solve for x
   x = 644,006.25/402.50
6. Step 6: Final answer
   x = 1,600.02