Finding the Fourth Proportional to 1,078.96, 1,488.72 and 636.64

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.96 : 1,488.72 = 636.64 : x
2. Step 2: Convert to fraction form
   1,078.96/1,488.72 = 636.64/x
3. Step 3: Cross multiply
   1,078.96x = 1,488.72 × 636.64
4. Step 4: Simplify right side
   1,078.96x = 947,778.70
5. Step 5: Solve for x
   x = 947,778.70/1,078.96
6. Step 6: Final answer
   x = 878.42