Finding the Fourth Proportional to 1,335.78, 1,843.47 and 811.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,335.78 : 1,843.47 = 811.71 : x
2. Step 2: Convert to fraction form
   1,335.78/1,843.47 = 811.71/x
3. Step 3: Cross multiply
   1,335.78x = 1,843.47 × 811.71
4. Step 4: Simplify right side
   1,335.78x = 1,496,363.03
5. Step 5: Solve for x
   x = 1,496,363.03/1,335.78
6. Step 6: Final answer
   x = 1,120.22