Finding the Fourth Proportional to 2,620.08, 3,929.31 and 864.69

Step by Step Solution

1. Step 1: Write the proportion equation
   2,620.08 : 3,929.31 = 864.69 : x
2. Step 2: Convert to fraction form
   2,620.08/3,929.31 = 864.69/x
3. Step 3: Cross multiply
   2,620.08x = 3,929.31 × 864.69
4. Step 4: Simplify right side
   2,620.08x = 3,397,635.06
5. Step 5: Solve for x
   x = 3,397,635.06/2,620.08
6. Step 6: Final answer
   x = 1,296.77