Finding the Third Proportional to 196.78 and 400.31

Step by Step Solution

1. Step 1: Write the proportion equation
   196.78 : 400.31 = 400.31 : x
2. Step 2: Convert to fraction form
   196.78/400.31 = 400.31/x
3. Step 3: Cross multiply
   196.78x = 400.31 × 400.31
4. Step 4: Simplify right side
   196.78x = 160,250.10
5. Step 5: Solve for x
   x = 160,250.10/196.78
6. Step 6: Final answer
   x = 814.36