Finding the Fourth Proportional to 1,162.71, 1,604.54 and 638.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,162.71 : 1,604.54 = 638.78 : x
2. Step 2: Convert to fraction form
   1,162.71/1,604.54 = 638.78/x
3. Step 3: Cross multiply
   1,162.71x = 1,604.54 × 638.78
4. Step 4: Simplify right side
   1,162.71x = 1,024,941.64
5. Step 5: Solve for x
   x = 1,024,941.64/1,162.71
6. Step 6: Final answer
   x = 881.51