Finding the Third Proportional to 256.50 and 394.59

Step by Step Solution

1. Step 1: Write the proportion equation
   256.50 : 394.59 = 394.59 : x
2. Step 2: Convert to fraction form
   256.50/394.59 = 394.59/x
3. Step 3: Cross multiply
   256.50x = 394.59 × 394.59
4. Step 4: Simplify right side
   256.50x = 155,704.23
5. Step 5: Solve for x
   x = 155,704.23/256.50
6. Step 6: Final answer
   x = 607.03