Finding the Third Proportional to 265.78 and 413.86

Step by Step Solution

1. Step 1: Write the proportion equation
   265.78 : 413.86 = 413.86 : x
2. Step 2: Convert to fraction form
   265.78/413.86 = 413.86/x
3. Step 3: Cross multiply
   265.78x = 413.86 × 413.86
4. Step 4: Simplify right side
   265.78x = 171,279.58
5. Step 5: Solve for x
   x = 171,279.58/265.78
6. Step 6: Final answer
   x = 644.44