Finding the Third Proportional to 287.88 and 648.31

Step by Step Solution

1. Step 1: Write the proportion equation
   287.88 : 648.31 = 648.31 : x
2. Step 2: Convert to fraction form
   287.88/648.31 = 648.31/x
3. Step 3: Cross multiply
   287.88x = 648.31 × 648.31
4. Step 4: Simplify right side
   287.88x = 420,309.10
5. Step 5: Solve for x
   x = 420,309.10/287.88
6. Step 6: Final answer
   x = 1,460.04