Finding the Fourth Proportional to 1,042.31, 1,438.24 and 885.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,042.31 : 1,438.24 = 885.57 : x
2. Step 2: Convert to fraction form
   1,042.31/1,438.24 = 885.57/x
3. Step 3: Cross multiply
   1,042.31x = 1,438.24 × 885.57
4. Step 4: Simplify right side
   1,042.31x = 1,273,662.20
5. Step 5: Solve for x
   x = 1,273,662.20/1,042.31
6. Step 6: Final answer
   x = 1,221.96