Finding the Fourth Proportional to 1,390.25, 1,918.58 and 800.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.25 : 1,918.58 = 800.69 : x
2. Step 2: Convert to fraction form
   1,390.25/1,918.58 = 800.69/x
3. Step 3: Cross multiply
   1,390.25x = 1,918.58 × 800.69
4. Step 4: Simplify right side
   1,390.25x = 1,536,183.82
5. Step 5: Solve for x
   x = 1,536,183.82/1,390.25
6. Step 6: Final answer
   x = 1,104.97