Finding the Third Proportional to 642.75 and 945.38

Step by Step Solution

1. Step 1: Write the proportion equation
   642.75 : 945.38 = 945.38 : x
2. Step 2: Convert to fraction form
   642.75/945.38 = 945.38/x
3. Step 3: Cross multiply
   642.75x = 945.38 × 945.38
4. Step 4: Simplify right side
   642.75x = 893,733.89
5. Step 5: Solve for x
   x = 893,733.89/642.75
6. Step 6: Final answer
   x = 1,390.48