Finding the Fourth Proportional to 1,578.83, 2,178.56 and 989.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,578.83 : 2,178.56 = 989.24 : x
2. Step 2: Convert to fraction form
   1,578.83/2,178.56 = 989.24/x
3. Step 3: Cross multiply
   1,578.83x = 2,178.56 × 989.24
4. Step 4: Simplify right side
   1,578.83x = 2,155,110.27
5. Step 5: Solve for x
   x = 2,155,110.27/1,578.83
6. Step 6: Final answer
   x = 1,365.01