Finding the Fourth Proportional to 1,131.31, 1,563.15 and 815.95

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.31 : 1,563.15 = 815.95 : x
2. Step 2: Convert to fraction form
   1,131.31/1,563.15 = 815.95/x
3. Step 3: Cross multiply
   1,131.31x = 1,563.15 × 815.95
4. Step 4: Simplify right side
   1,131.31x = 1,275,452.24
5. Step 5: Solve for x
   x = 1,275,452.24/1,131.31
6. Step 6: Final answer
   x = 1,127.41