Finding the Third Proportional to 103.78 and 199.31

Step by Step Solution

1. Step 1: Write the proportion equation
   103.78 : 199.31 = 199.31 : x
2. Step 2: Convert to fraction form
   103.78/199.31 = 199.31/x
3. Step 3: Cross multiply
   103.78x = 199.31 × 199.31
4. Step 4: Simplify right side
   103.78x = 39,725.47
5. Step 5: Solve for x
   x = 39,725.47/103.78
6. Step 6: Final answer
   x = 382.78