Finding the Third Proportional to 378.11 and 618.89

Step by Step Solution

1. Step 1: Write the proportion equation
   378.11 : 618.89 = 618.89 : x
2. Step 2: Convert to fraction form
   378.11/618.89 = 618.89/x
3. Step 3: Cross multiply
   378.11x = 618.89 × 618.89
4. Step 4: Simplify right side
   378.11x = 383,025.61
5. Step 5: Solve for x
   x = 383,025.61/378.11
6. Step 6: Final answer
   x = 1,013.01