Finding the Fourth Proportional to 1,078.51, 1,488.35 and 636.41

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.51 : 1,488.35 = 636.41 : x
2. Step 2: Convert to fraction form
   1,078.51/1,488.35 = 636.41/x
3. Step 3: Cross multiply
   1,078.51x = 1,488.35 × 636.41
4. Step 4: Simplify right side
   1,078.51x = 947,200.82
5. Step 5: Solve for x
   x = 947,200.82/1,078.51
6. Step 6: Final answer
   x = 878.25