Finding the Fourth Proportional to 1,079.11, 1,488.72 and 636.85

Step by Step Solution

1. Step 1: Write the proportion equation
   1,079.11 : 1,488.72 = 636.85 : x
2. Step 2: Convert to fraction form
   1,079.11/1,488.72 = 636.85/x
3. Step 3: Cross multiply
   1,079.11x = 1,488.72 × 636.85
4. Step 4: Simplify right side
   1,079.11x = 948,091.33
5. Step 5: Solve for x
   x = 948,091.33/1,079.11
6. Step 6: Final answer
   x = 878.59