Finding the Fourth Proportional to 1,380.80, 1,904.94 and 791.01

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.80 : 1,904.94 = 791.01 : x
2. Step 2: Convert to fraction form
   1,380.80/1,904.94 = 791.01/x
3. Step 3: Cross multiply
   1,380.80x = 1,904.94 × 791.01
4. Step 4: Simplify right side
   1,380.80x = 1,506,826.59
5. Step 5: Solve for x
   x = 1,506,826.59/1,380.80
6. Step 6: Final answer
   x = 1,091.27