Finding the Fourth Proportional to 1,143.59, 1,578.15 and 646.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,143.59 : 1,578.15 = 646.18 : x
2. Step 2: Convert to fraction form
   1,143.59/1,578.15 = 646.18/x
3. Step 3: Cross multiply
   1,143.59x = 1,578.15 × 646.18
4. Step 4: Simplify right side
   1,143.59x = 1,019,765.02
5. Step 5: Solve for x
   x = 1,019,765.02/1,143.59
6. Step 6: Final answer
   x = 891.73