Finding the Fourth Proportional to 2,638.98, 3,958.17 and 691.34

Step by Step Solution

1. Step 1: Write the proportion equation
   2,638.98 : 3,958.17 = 691.34 : x
2. Step 2: Convert to fraction form
   2,638.98/3,958.17 = 691.34/x
3. Step 3: Cross multiply
   2,638.98x = 3,958.17 × 691.34
4. Step 4: Simplify right side
   2,638.98x = 2,736,418.86
5. Step 5: Solve for x
   x = 2,736,418.86/2,638.98
6. Step 6: Final answer
   x = 1,036.92