Finding the Fourth Proportional to 1,020.34, 1,407.89 and 578.11

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.34 : 1,407.89 = 578.11 : x
2. Step 2: Convert to fraction form
   1,020.34/1,407.89 = 578.11/x
3. Step 3: Cross multiply
   1,020.34x = 1,407.89 × 578.11
4. Step 4: Simplify right side
   1,020.34x = 813,912.40
5. Step 5: Solve for x
   x = 813,912.40/1,020.34
6. Step 6: Final answer
   x = 797.69