Finding the Fourth Proportional to 1,078.74, 1,488.06 and 636.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.74 : 1,488.06 = 636.58 : x
2. Step 2: Convert to fraction form
   1,078.74/1,488.06 = 636.58/x
3. Step 3: Cross multiply
   1,078.74x = 1,488.06 × 636.58
4. Step 4: Simplify right side
   1,078.74x = 947,269.23
5. Step 5: Solve for x
   x = 947,269.23/1,078.74
6. Step 6: Final answer
   x = 878.13