Finding the Fourth Proportional to 2,638.64, 3,959.31 and 1,340.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,638.64 : 3,959.31 = 1,340.12 : x
2. Step 2: Convert to fraction form
   2,638.64/3,959.31 = 1,340.12/x
3. Step 3: Cross multiply
   2,638.64x = 3,959.31 × 1,340.12
4. Step 4: Simplify right side
   2,638.64x = 5,305,950.52
5. Step 5: Solve for x
   x = 5,305,950.52/2,638.64
6. Step 6: Final answer
   x = 2,010.87