Finding the Third Proportional to 390.75 and 789.38

Step by Step Solution

1. Step 1: Write the proportion equation
   390.75 : 789.38 = 789.38 : x
2. Step 2: Convert to fraction form
   390.75/789.38 = 789.38/x
3. Step 3: Cross multiply
   390.75x = 789.38 × 789.38
4. Step 4: Simplify right side
   390.75x = 623,112.89
5. Step 5: Solve for x
   x = 623,112.89/390.75
6. Step 6: Final answer
   x = 1,594.66