Finding the Third Proportional to 318.38 and 429.56

Step by Step Solution

1. Step 1: Write the proportion equation
   318.38 : 429.56 = 429.56 : x
2. Step 2: Convert to fraction form
   318.38/429.56 = 429.56/x
3. Step 3: Cross multiply
   318.38x = 429.56 × 429.56
4. Step 4: Simplify right side
   318.38x = 184,523.94
5. Step 5: Solve for x
   x = 184,523.94/318.38
6. Step 6: Final answer
   x = 579.58