Finding the Fourth Proportional to 1,380.89, 1,905.63 and 791.75

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.89 : 1,905.63 = 791.75 : x
2. Step 2: Convert to fraction form
   1,380.89/1,905.63 = 791.75/x
3. Step 3: Cross multiply
   1,380.89x = 1,905.63 × 791.75
4. Step 4: Simplify right side
   1,380.89x = 1,508,782.55
5. Step 5: Solve for x
   x = 1,508,782.55/1,380.89
6. Step 6: Final answer
   x = 1,092.62