Finding the Fourth Proportional to 1,389.39, 1,917.33 and 799.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.39 : 1,917.33 = 799.89 : x
2. Step 2: Convert to fraction form
   1,389.39/1,917.33 = 799.89/x
3. Step 3: Cross multiply
   1,389.39x = 1,917.33 × 799.89
4. Step 4: Simplify right side
   1,389.39x = 1,533,653.09
5. Step 5: Solve for x
   x = 1,533,653.09/1,389.39
6. Step 6: Final answer
   x = 1,103.83