Finding the Fourth Proportional to 1,009.78, 1,391.82 and 810.04

Step by Step Solution

1. Step 1: Write the proportion equation
   1,009.78 : 1,391.82 = 810.04 : x
2. Step 2: Convert to fraction form
   1,009.78/1,391.82 = 810.04/x
3. Step 3: Cross multiply
   1,009.78x = 1,391.82 × 810.04
4. Step 4: Simplify right side
   1,009.78x = 1,127,436.23
5. Step 5: Solve for x
   x = 1,127,436.23/1,009.78
6. Step 6: Final answer
   x = 1,116.52