Finding the Fourth Proportional to 1,078.53, 1,488.39 and 612.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.53 : 1,488.39 = 612.78 : x
2. Step 2: Convert to fraction form
   1,078.53/1,488.39 = 612.78/x
3. Step 3: Cross multiply
   1,078.53x = 1,488.39 × 612.78
4. Step 4: Simplify right side
   1,078.53x = 912,055.62
5. Step 5: Solve for x
   x = 912,055.62/1,078.53
6. Step 6: Final answer
   x = 845.65