Finding the Fourth Proportional to 1,020.20, 1,407.89 and 578.01

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.20 : 1,407.89 = 578.01 : x
2. Step 2: Convert to fraction form
   1,020.20/1,407.89 = 578.01/x
3. Step 3: Cross multiply
   1,020.20x = 1,407.89 × 578.01
4. Step 4: Simplify right side
   1,020.20x = 813,775.94
5. Step 5: Solve for x
   x = 813,775.94/1,020.20
6. Step 6: Final answer
   x = 797.67