Finding the Fourth Proportional to 2,658.87, 3,988.76 and 809.55

Step by Step Solution

1. Step 1: Write the proportion equation
   2,658.87 : 3,988.76 = 809.55 : x
2. Step 2: Convert to fraction form
   2,658.87/3,988.76 = 809.55/x
3. Step 3: Cross multiply
   2,658.87x = 3,988.76 × 809.55
4. Step 4: Simplify right side
   2,658.87x = 3,229,096.61
5. Step 5: Solve for x
   x = 3,229,096.61/2,658.87
6. Step 6: Final answer
   x = 1,214.46