Finding the Fourth Proportional to 1,389.42, 1,917.42 and 791.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.42 : 1,917.42 = 791.83 : x
2. Step 2: Convert to fraction form
   1,389.42/1,917.42 = 791.83/x
3. Step 3: Cross multiply
   1,389.42x = 1,917.42 × 791.83
4. Step 4: Simplify right side
   1,389.42x = 1,518,270.68
5. Step 5: Solve for x
   x = 1,518,270.68/1,389.42
6. Step 6: Final answer
   x = 1,092.74