Finding the Fourth Proportional to 1,399.98, 2,099.43 and 578.04

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.98 : 2,099.43 = 578.04 : x
2. Step 2: Convert to fraction form
   1,399.98/2,099.43 = 578.04/x
3. Step 3: Cross multiply
   1,399.98x = 2,099.43 × 578.04
4. Step 4: Simplify right side
   1,399.98x = 1,213,554.52
5. Step 5: Solve for x
   x = 1,213,554.52/1,399.98
6. Step 6: Final answer
   x = 866.84