Finding the Fourth Proportional to 1,162.80, 1,604.56 and 638.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,162.80 : 1,604.56 = 638.86 : x
2. Step 2: Convert to fraction form
   1,162.80/1,604.56 = 638.86/x
3. Step 3: Cross multiply
   1,162.80x = 1,604.56 × 638.86
4. Step 4: Simplify right side
   1,162.80x = 1,025,089.20
5. Step 5: Solve for x
   x = 1,025,089.20/1,162.80
6. Step 6: Final answer
   x = 881.57