Finding the Third Proportional to 256.29 and 388.71

Step by Step Solution

1. Step 1: Write the proportion equation
   256.29 : 388.71 = 388.71 : x
2. Step 2: Convert to fraction form
   256.29/388.71 = 388.71/x
3. Step 3: Cross multiply
   256.29x = 388.71 × 388.71
4. Step 4: Simplify right side
   256.29x = 151,091.64
5. Step 5: Solve for x
   x = 151,091.64/256.29
6. Step 6: Final answer
   x = 589.54