Finding the Fourth Proportional to 1,231.49, 1,699.02 and 811.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,231.49 : 1,699.02 = 811.71 : x
2. Step 2: Convert to fraction form
   1,231.49/1,699.02 = 811.71/x
3. Step 3: Cross multiply
   1,231.49x = 1,699.02 × 811.71
4. Step 4: Simplify right side
   1,231.49x = 1,379,111.52
5. Step 5: Solve for x
   x = 1,379,111.52/1,231.49
6. Step 6: Final answer
   x = 1,119.88