Finding the Fourth Proportional to 2,390.69, 3,585.28 and 809.10

Step by Step Solution

1. Step 1: Write the proportion equation
   2,390.69 : 3,585.28 = 809.10 : x
2. Step 2: Convert to fraction form
   2,390.69/3,585.28 = 809.10/x
3. Step 3: Cross multiply
   2,390.69x = 3,585.28 × 809.10
4. Step 4: Simplify right side
   2,390.69x = 2,900,850.05
5. Step 5: Solve for x
   x = 2,900,850.05/2,390.69
6. Step 6: Final answer
   x = 1,213.39