Finding the Fourth Proportional to 1,078.55, 1,488.21 and 636.53

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.55 : 1,488.21 = 636.53 : x
2. Step 2: Convert to fraction form
   1,078.55/1,488.21 = 636.53/x
3. Step 3: Cross multiply
   1,078.55x = 1,488.21 × 636.53
4. Step 4: Simplify right side
   1,078.55x = 947,294.03
5. Step 5: Solve for x
   x = 947,294.03/1,078.55
6. Step 6: Final answer
   x = 878.31