Finding the Fourth Proportional to 1,078.74, 1,488.74 and 636.53

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.74 : 1,488.74 = 636.53 : x
2. Step 2: Convert to fraction form
   1,078.74/1,488.74 = 636.53/x
3. Step 3: Cross multiply
   1,078.74x = 1,488.74 × 636.53
4. Step 4: Simplify right side
   1,078.74x = 947,617.05
5. Step 5: Solve for x
   x = 947,617.05/1,078.74
6. Step 6: Final answer
   x = 878.45