Finding the Fourth Proportional to 1,343.12, 1,853.78 and 811.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,343.12 : 1,853.78 = 811.89 : x
2. Step 2: Convert to fraction form
   1,343.12/1,853.78 = 811.89/x
3. Step 3: Cross multiply
   1,343.12x = 1,853.78 × 811.89
4. Step 4: Simplify right side
   1,343.12x = 1,505,061.38
5. Step 5: Solve for x
   x = 1,505,061.38/1,343.12
6. Step 6: Final answer
   x = 1,120.58