Finding the Fourth Proportional to 1,315.68, 1,815.59 and 791.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,315.68 : 1,815.59 = 791.61 : x
2. Step 2: Convert to fraction form
   1,315.68/1,815.59 = 791.61/x
3. Step 3: Cross multiply
   1,315.68x = 1,815.59 × 791.61
4. Step 4: Simplify right side
   1,315.68x = 1,437,229.92
5. Step 5: Solve for x
   x = 1,437,229.92/1,315.68
6. Step 6: Final answer
   x = 1,092.39