Finding the Fourth Proportional to 1,078.88, 1,488.68 and 636.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.88 : 1,488.68 = 636.72 : x
2. Step 2: Convert to fraction form
   1,078.88/1,488.68 = 636.72/x
3. Step 3: Cross multiply
   1,078.88x = 1,488.68 × 636.72
4. Step 4: Simplify right side
   1,078.88x = 947,872.33
5. Step 5: Solve for x
   x = 947,872.33/1,078.88
6. Step 6: Final answer
   x = 878.57