Finding the Fourth Proportional to 1,315.59, 1,815.82 and 818.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,315.59 : 1,815.82 = 818.61 : x
2. Step 2: Convert to fraction form
   1,315.59/1,815.82 = 818.61/x
3. Step 3: Cross multiply
   1,315.59x = 1,815.82 × 818.61
4. Step 4: Simplify right side
   1,315.59x = 1,486,448.41
5. Step 5: Solve for x
   x = 1,486,448.41/1,315.59
6. Step 6: Final answer
   x = 1,129.87