Finding the Fourth Proportional to 1,162.78, 1,604.59 and 638.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,162.78 : 1,604.59 = 638.78 : x
2. Step 2: Convert to fraction form
   1,162.78/1,604.59 = 638.78/x
3. Step 3: Cross multiply
   1,162.78x = 1,604.59 × 638.78
4. Step 4: Simplify right side
   1,162.78x = 1,024,980.00
5. Step 5: Solve for x
   x = 1,024,980.00/1,162.78
6. Step 6: Final answer
   x = 881.49