Finding the Fourth Proportional to 1,143.76, 1,578.22 and 646.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,143.76 : 1,578.22 = 646.24 : x
2. Step 2: Convert to fraction form
   1,143.76/1,578.22 = 646.24/x
3. Step 3: Cross multiply
   1,143.76x = 1,578.22 × 646.24
4. Step 4: Simplify right side
   1,143.76x = 1,019,908.89
5. Step 5: Solve for x
   x = 1,019,908.89/1,143.76
6. Step 6: Final answer
   x = 891.72