Finding the Third Proportional to 198.50 and 402.50

Step by Step Solution

1. Step 1: Write the proportion equation
   198.50 : 402.50 = 402.50 : x
2. Step 2: Convert to fraction form
   198.50/402.50 = 402.50/x
3. Step 3: Cross multiply
   198.50x = 402.50 × 402.50
4. Step 4: Simplify right side
   198.50x = 162,006.25
5. Step 5: Solve for x
   x = 162,006.25/198.50
6. Step 6: Final answer
   x = 816.15