Finding the Fourth Proportional to 1,288.29, 1,777.89 and 791.22

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.29 : 1,777.89 = 791.22 : x
2. Step 2: Convert to fraction form
   1,288.29/1,777.89 = 791.22/x
3. Step 3: Cross multiply
   1,288.29x = 1,777.89 × 791.22
4. Step 4: Simplify right side
   1,288.29x = 1,406,702.13
5. Step 5: Solve for x
   x = 1,406,702.13/1,288.29
6. Step 6: Final answer
   x = 1,091.91