Finding the Fourth Proportional to 2,638.72, 3,957.92 and 690.88

Step by Step Solution

1. Step 1: Write the proportion equation
   2,638.72 : 3,957.92 = 690.88 : x
2. Step 2: Convert to fraction form
   2,638.72/3,957.92 = 690.88/x
3. Step 3: Cross multiply
   2,638.72x = 3,957.92 × 690.88
4. Step 4: Simplify right side
   2,638.72x = 2,734,447.77
5. Step 5: Solve for x
   x = 2,734,447.77/2,638.72
6. Step 6: Final answer
   x = 1,036.28