Finding the Fourth Proportional to 2,619.91, 3,930.35 and 865.04

Step by Step Solution

1. Step 1: Write the proportion equation
   2,619.91 : 3,930.35 = 865.04 : x
2. Step 2: Convert to fraction form
   2,619.91/3,930.35 = 865.04/x
3. Step 3: Cross multiply
   2,619.91x = 3,930.35 × 865.04
4. Step 4: Simplify right side
   2,619.91x = 3,399,905.84
5. Step 5: Solve for x
   x = 3,399,905.84/2,619.91
6. Step 6: Final answer
   x = 1,297.72