Finding the Third Proportional to 136.78 and 321.56

Step by Step Solution

1. Step 1: Write the proportion equation
   136.78 : 321.56 = 321.56 : x
2. Step 2: Convert to fraction form
   136.78/321.56 = 321.56/x
3. Step 3: Cross multiply
   136.78x = 321.56 × 321.56
4. Step 4: Simplify right side
   136.78x = 103,402.44
5. Step 5: Solve for x
   x = 103,402.44/136.78
6. Step 6: Final answer
   x = 755.97