Finding the Fourth Proportional to 1,380.66, 1,905.42 and 791.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.66 : 1,905.42 = 791.38 : x
2. Step 2: Convert to fraction form
   1,380.66/1,905.42 = 791.38/x
3. Step 3: Cross multiply
   1,380.66x = 1,905.42 × 791.38
4. Step 4: Simplify right side
   1,380.66x = 1,507,911.28
5. Step 5: Solve for x
   x = 1,507,911.28/1,380.66
6. Step 6: Final answer
   x = 1,092.17