Finding the Fourth Proportional to 1,389.69, 1,917.59 and 800.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.69 : 1,917.59 = 800.42 : x
2. Step 2: Convert to fraction form
   1,389.69/1,917.59 = 800.42/x
3. Step 3: Cross multiply
   1,389.69x = 1,917.59 × 800.42
4. Step 4: Simplify right side
   1,389.69x = 1,534,863.80
5. Step 5: Solve for x
   x = 1,534,863.80/1,389.69
6. Step 6: Final answer
   x = 1,104.46