Finding the Third Proportional to 99.50 and 199.50

Step by Step Solution

1. Step 1: Write the proportion equation
   99.50 : 199.50 = 199.50 : x
2. Step 2: Convert to fraction form
   99.50/199.50 = 199.50/x
3. Step 3: Cross multiply
   99.50x = 199.50 × 199.50
4. Step 4: Simplify right side
   99.50x = 39,800.25
5. Step 5: Solve for x
   x = 39,800.25/99.50
6. Step 6: Final answer
   x = 400.00