Finding the Third Proportional to 256.50 and 389.25

Step by Step Solution

1. Step 1: Write the proportion equation
   256.50 : 389.25 = 389.25 : x
2. Step 2: Convert to fraction form
   256.50/389.25 = 389.25/x
3. Step 3: Cross multiply
   256.50x = 389.25 × 389.25
4. Step 4: Simplify right side
   256.50x = 151,515.56
5. Step 5: Solve for x
   x = 151,515.56/256.50
6. Step 6: Final answer
   x = 590.70