Finding the Third Proportional to 426.75 and 642.56

Step by Step Solution

1. Step 1: Write the proportion equation
   426.75 : 642.56 = 642.56 : x
2. Step 2: Convert to fraction form
   426.75/642.56 = 642.56/x
3. Step 3: Cross multiply
   426.75x = 642.56 × 642.56
4. Step 4: Simplify right side
   426.75x = 412,886.57
5. Step 5: Solve for x
   x = 412,886.57/426.75
6. Step 6: Final answer
   x = 967.51