Finding the Fourth Proportional to 1,012.31, 1,396.89 and 570.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,012.31 : 1,396.89 = 570.28 : x
2. Step 2: Convert to fraction form
   1,012.31/1,396.89 = 570.28/x
3. Step 3: Cross multiply
   1,012.31x = 1,396.89 × 570.28
4. Step 4: Simplify right side
   1,012.31x = 796,614.94
5. Step 5: Solve for x
   x = 796,614.94/1,012.31
6. Step 6: Final answer
   x = 786.93