Finding the Third Proportional to 128 and 245.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128 : 245.50 = 245.50 : x
2. Step 2: Convert to fraction form
   128/245.50 = 245.50/x
3. Step 3: Cross multiply
   128x = 245.50 × 245.50
4. Step 4: Simplify right side
   128x = 60,270.25
5. Step 5: Solve for x
   x = 60,270.25/128
6. Step 6: Final answer
   x = 470.86