Finding the Fourth Proportional to 1,143.69, 1,578.28 and 646.49

Step by Step Solution

1. Step 1: Write the proportion equation
   1,143.69 : 1,578.28 = 646.49 : x
2. Step 2: Convert to fraction form
   1,143.69/1,578.28 = 646.49/x
3. Step 3: Cross multiply
   1,143.69x = 1,578.28 × 646.49
4. Step 4: Simplify right side
   1,143.69x = 1,020,345.78
5. Step 5: Solve for x
   x = 1,020,345.78/1,143.69
6. Step 6: Final answer
   x = 892.15