Finding the Fourth Proportional to 1,143.79, 1,578.42 and 619.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,143.79 : 1,578.42 = 619.82 : x
2. Step 2: Convert to fraction form
   1,143.79/1,578.42 = 619.82/x
3. Step 3: Cross multiply
   1,143.79x = 1,578.42 × 619.82
4. Step 4: Simplify right side
   1,143.79x = 978,328.39
5. Step 5: Solve for x
   x = 978,328.39/1,143.79
6. Step 6: Final answer
   x = 855.34