Finding the Third Proportional to 616.78 and 1,216.69

Step by Step Solution

1. Step 1: Write the proportion equation
   616.78 : 1,216.69 = 1,216.69 : x
2. Step 2: Convert to fraction form
   616.78/1,216.69 = 1,216.69/x
3. Step 3: Cross multiply
   616.78x = 1,216.69 × 1,216.69
4. Step 4: Simplify right side
   616.78x = 1,480,328.47
5. Step 5: Solve for x
   x = 1,480,328.47/616.78
6. Step 6: Final answer
   x = 2,400.09