Finding the Fourth Proportional to 1,315.33, 1,815.77 and 818.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,315.33 : 1,815.77 = 818.30 : x
2. Step 2: Convert to fraction form
   1,315.33/1,815.77 = 818.30/x
3. Step 3: Cross multiply
   1,315.33x = 1,815.77 × 818.30
4. Step 4: Simplify right side
   1,315.33x = 1,485,844.59
5. Step 5: Solve for x
   x = 1,485,844.59/1,315.33
6. Step 6: Final answer
   x = 1,129.64