Finding the Fourth Proportional to 1,078.90, 1,488.72 and 636.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.90 : 1,488.72 = 636.94 : x
2. Step 2: Convert to fraction form
   1,078.90/1,488.72 = 636.94/x
3. Step 3: Cross multiply
   1,078.90x = 1,488.72 × 636.94
4. Step 4: Simplify right side
   1,078.90x = 948,225.32
5. Step 5: Solve for x
   x = 948,225.32/1,078.90
6. Step 6: Final answer
   x = 878.88