Finding the Fourth Proportional to 1,078.68, 1,488.61 and 636.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.68 : 1,488.61 = 636.58 : x
2. Step 2: Convert to fraction form
   1,078.68/1,488.61 = 636.58/x
3. Step 3: Cross multiply
   1,078.68x = 1,488.61 × 636.58
4. Step 4: Simplify right side
   1,078.68x = 947,616.16
5. Step 5: Solve for x
   x = 947,616.16/1,078.68
6. Step 6: Final answer
   x = 878.50