Finding the Fourth Proportional to 1,123.83, 1,686.65 and 815.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.83 : 1,686.65 = 815.82 : x
2. Step 2: Convert to fraction form
   1,123.83/1,686.65 = 815.82/x
3. Step 3: Cross multiply
   1,123.83x = 1,686.65 × 815.82
4. Step 4: Simplify right side
   1,123.83x = 1,375,998.72
5. Step 5: Solve for x
   x = 1,375,998.72/1,123.83
6. Step 6: Final answer
   x = 1,224.38