Finding the Fourth Proportional to 1,020.28, 1,408.01 and 578.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.28 : 1,408.01 = 578.09 : x
2. Step 2: Convert to fraction form
   1,020.28/1,408.01 = 578.09/x
3. Step 3: Cross multiply
   1,020.28x = 1,408.01 × 578.09
4. Step 4: Simplify right side
   1,020.28x = 813,956.50
5. Step 5: Solve for x
   x = 813,956.50/1,020.28
6. Step 6: Final answer
   x = 797.78