Finding the Third Proportional to 273.56 and 642.56

Step by Step Solution

1. Step 1: Write the proportion equation
   273.56 : 642.56 = 642.56 : x
2. Step 2: Convert to fraction form
   273.56/642.56 = 642.56/x
3. Step 3: Cross multiply
   273.56x = 642.56 × 642.56
4. Step 4: Simplify right side
   273.56x = 412,886.57
5. Step 5: Solve for x
   x = 412,886.57/273.56
6. Step 6: Final answer
   x = 1,509.30