Finding the Third Proportional to 620.72 and 1,291.78

Step by Step Solution

1. Step 1: Write the proportion equation
   620.72 : 1,291.78 = 1,291.78 : x
2. Step 2: Convert to fraction form
   620.72/1,291.78 = 1,291.78/x
3. Step 3: Cross multiply
   620.72x = 1,291.78 × 1,291.78
4. Step 4: Simplify right side
   620.72x = 1,668,698.80
5. Step 5: Solve for x
   x = 1,668,698.80/620.72
6. Step 6: Final answer
   x = 2,688.33