Finding the Third Proportional to 263.38 and 398.69

Step by Step Solution

1. Step 1: Write the proportion equation
   263.38 : 398.69 = 398.69 : x
2. Step 2: Convert to fraction form
   263.38/398.69 = 398.69/x
3. Step 3: Cross multiply
   263.38x = 398.69 × 398.69
4. Step 4: Simplify right side
   263.38x = 158,951.72
5. Step 5: Solve for x
   x = 158,951.72/263.38
6. Step 6: Final answer
   x = 603.52