Finding the Fourth Proportional to 1,111.59, 1,665.90 and 865.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.59 : 1,665.90 = 865.09 : x
2. Step 2: Convert to fraction form
   1,111.59/1,665.90 = 865.09/x
3. Step 3: Cross multiply
   1,111.59x = 1,665.90 × 865.09
4. Step 4: Simplify right side
   1,111.59x = 1,441,153.43
5. Step 5: Solve for x
   x = 1,441,153.43/1,111.59
6. Step 6: Final answer
   x = 1,296.48