Finding the Fourth Proportional to 1,399.59, 2,099.49 and 578.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.59 : 2,099.49 = 578.25 : x
2. Step 2: Convert to fraction form
   1,399.59/2,099.49 = 578.25/x
3. Step 3: Cross multiply
   1,399.59x = 2,099.49 × 578.25
4. Step 4: Simplify right side
   1,399.59x = 1,214,030.09
5. Step 5: Solve for x
   x = 1,214,030.09/1,399.59
6. Step 6: Final answer
   x = 867.42