Finding the Third Proportional to 289.69 and 396.56

Step by Step Solution

1. Step 1: Write the proportion equation
   289.69 : 396.56 = 396.56 : x
2. Step 2: Convert to fraction form
   289.69/396.56 = 396.56/x
3. Step 3: Cross multiply
   289.69x = 396.56 × 396.56
4. Step 4: Simplify right side
   289.69x = 157,261.82
5. Step 5: Solve for x
   x = 157,261.82/289.69
6. Step 6: Final answer
   x = 542.87