Finding the Third Proportional to 249.50 and 401.50

Step by Step Solution

1. Step 1: Write the proportion equation
   249.50 : 401.50 = 401.50 : x
2. Step 2: Convert to fraction form
   249.50/401.50 = 401.50/x
3. Step 3: Cross multiply
   249.50x = 401.50 × 401.50
4. Step 4: Simplify right side
   249.50x = 161,202.25
5. Step 5: Solve for x
   x = 161,202.25/249.50
6. Step 6: Final answer
   x = 646.10