Finding the Third Proportional to 328.78 and 388.78

Step by Step Solution

1. Step 1: Write the proportion equation
   328.78 : 388.78 = 388.78 : x
2. Step 2: Convert to fraction form
   328.78/388.78 = 388.78/x
3. Step 3: Cross multiply
   328.78x = 388.78 × 388.78
4. Step 4: Simplify right side
   328.78x = 151,150.86
5. Step 5: Solve for x
   x = 151,150.86/328.78
6. Step 6: Final answer
   x = 459.73