Finding the Fourth Proportional to 1,335.57, 1,843.20 and 811.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,335.57 : 1,843.20 = 811.91 : x
2. Step 2: Convert to fraction form
   1,335.57/1,843.20 = 811.91/x
3. Step 3: Cross multiply
   1,335.57x = 1,843.20 × 811.91
4. Step 4: Simplify right side
   1,335.57x = 1,496,503.30
5. Step 5: Solve for x
   x = 1,496,503.30/1,335.57
6. Step 6: Final answer
   x = 1,120.50