Finding the Third Proportional to 397.31 and 618.56

Step by Step Solution

1. Step 1: Write the proportion equation
   397.31 : 618.56 = 618.56 : x
2. Step 2: Convert to fraction form
   397.31/618.56 = 618.56/x
3. Step 3: Cross multiply
   397.31x = 618.56 × 618.56
4. Step 4: Simplify right side
   397.31x = 382,619.57
5. Step 5: Solve for x
   x = 382,619.57/397.31
6. Step 6: Final answer
   x = 963.02