Finding the Fourth Proportional to 1,308.62, 1,805.83 and 811.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,308.62 : 1,805.83 = 811.31 : x
2. Step 2: Convert to fraction form
   1,308.62/1,805.83 = 811.31/x
3. Step 3: Cross multiply
   1,308.62x = 1,805.83 × 811.31
4. Step 4: Simplify right side
   1,308.62x = 1,465,076.88
5. Step 5: Solve for x
   x = 1,465,076.88/1,308.62
6. Step 6: Final answer
   x = 1,119.56