Finding the Fourth Proportional to 2,606.69, 3,909.67 and 658.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,606.69 : 3,909.67 = 658.78 : x
2. Step 2: Convert to fraction form
   2,606.69/3,909.67 = 658.78/x
3. Step 3: Cross multiply
   2,606.69x = 3,909.67 × 658.78
4. Step 4: Simplify right side
   2,606.69x = 2,575,612.40
5. Step 5: Solve for x
   x = 2,575,612.40/2,606.69
6. Step 6: Final answer
   x = 988.08