Finding the Third Proportional to 278.72 and 610.31

Step by Step Solution

1. Step 1: Write the proportion equation
   278.72 : 610.31 = 610.31 : x
2. Step 2: Convert to fraction form
   278.72/610.31 = 610.31/x
3. Step 3: Cross multiply
   278.72x = 610.31 × 610.31
4. Step 4: Simplify right side
   278.72x = 372,481.35
5. Step 5: Solve for x
   x = 372,481.35/278.72
6. Step 6: Final answer
   x = 1,336.41