Finding the Third Proportional to 144.28 and 315.56

Step by Step Solution

1. Step 1: Write the proportion equation
   144.28 : 315.56 = 315.56 : x
2. Step 2: Convert to fraction form
   144.28/315.56 = 315.56/x
3. Step 3: Cross multiply
   144.28x = 315.56 × 315.56
4. Step 4: Simplify right side
   144.28x = 99,579.69
5. Step 5: Solve for x
   x = 99,579.69/144.28
6. Step 6: Final answer
   x = 690.18