Finding the Fourth Proportional to 1,143.89, 1,578.56 and 619.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,143.89 : 1,578.56 = 619.92 : x
2. Step 2: Convert to fraction form
   1,143.89/1,578.56 = 619.92/x
3. Step 3: Cross multiply
   1,143.89x = 1,578.56 × 619.92
4. Step 4: Simplify right side
   1,143.89x = 978,577.82
5. Step 5: Solve for x
   x = 978,577.82/1,143.89
6. Step 6: Final answer
   x = 855.48