Finding the Fourth Proportional to 1,078.50, 1,488.34 and 636.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.50 : 1,488.34 = 636.42 : x
2. Step 2: Convert to fraction form
   1,078.50/1,488.34 = 636.42/x
3. Step 3: Cross multiply
   1,078.50x = 1,488.34 × 636.42
4. Step 4: Simplify right side
   1,078.50x = 947,209.34
5. Step 5: Solve for x
   x = 947,209.34/1,078.50
6. Step 6: Final answer
   x = 878.27