Finding the Fourth Proportional to 1,162.89, 1,604.75 and 638.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,162.89 : 1,604.75 = 638.91 : x
2. Step 2: Convert to fraction form
   1,162.89/1,604.75 = 638.91/x
3. Step 3: Cross multiply
   1,162.89x = 1,604.75 × 638.91
4. Step 4: Simplify right side
   1,162.89x = 1,025,290.82
5. Step 5: Solve for x
   x = 1,025,290.82/1,162.89
6. Step 6: Final answer
   x = 881.67