Finding the Fourth Proportional to 1,162.72, 1,604.56 and 638.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,162.72 : 1,604.56 = 638.80 : x
2. Step 2: Convert to fraction form
   1,162.72/1,604.56 = 638.80/x
3. Step 3: Cross multiply
   1,162.72x = 1,604.56 × 638.80
4. Step 4: Simplify right side
   1,162.72x = 1,024,992.93
5. Step 5: Solve for x
   x = 1,024,992.93/1,162.72
6. Step 6: Final answer
   x = 881.55