Finding the Fourth Proportional to 2,620.89, 3,929.45 and 864.92

Step by Step Solution

1. Step 1: Write the proportion equation
   2,620.89 : 3,929.45 = 864.92 : x
2. Step 2: Convert to fraction form
   2,620.89/3,929.45 = 864.92/x
3. Step 3: Cross multiply
   2,620.89x = 3,929.45 × 864.92
4. Step 4: Simplify right side
   2,620.89x = 3,398,659.89
5. Step 5: Solve for x
   x = 3,398,659.89/2,620.89
6. Step 6: Final answer
   x = 1,296.76