Finding the Third Proportional to 255.50 and 393.45

Step by Step Solution

1. Step 1: Write the proportion equation
   255.50 : 393.45 = 393.45 : x
2. Step 2: Convert to fraction form
   255.50/393.45 = 393.45/x
3. Step 3: Cross multiply
   255.50x = 393.45 × 393.45
4. Step 4: Simplify right side
   255.50x = 154,803.82
5. Step 5: Solve for x
   x = 154,803.82/255.50
6. Step 6: Final answer
   x = 605.89