Finding the Third Proportional to 665.50 and 998.50

Step by Step Solution

1. Step 1: Write the proportion equation
   665.50 : 998.50 = 998.50 : x
2. Step 2: Convert to fraction form
   665.50/998.50 = 998.50/x
3. Step 3: Cross multiply
   665.50x = 998.50 × 998.50
4. Step 4: Simplify right side
   665.50x = 997,002.25
5. Step 5: Solve for x
   x = 997,002.25/665.50
6. Step 6: Final answer
   x = 1,498.13