Finding the Fourth Proportional to 1,012.84, 1,397.72 and 570.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,012.84 : 1,397.72 = 570.78 : x
2. Step 2: Convert to fraction form
   1,012.84/1,397.72 = 570.78/x
3. Step 3: Cross multiply
   1,012.84x = 1,397.72 × 570.78
4. Step 4: Simplify right side
   1,012.84x = 797,792.05
5. Step 5: Solve for x
   x = 797,792.05/1,012.84
6. Step 6: Final answer
   x = 787.68