Finding the Fourth Proportional to 1,355.76, 1,871.12 and 766.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.76 : 1,871.12 = 766.28 : x
2. Step 2: Convert to fraction form
   1,355.76/1,871.12 = 766.28/x
3. Step 3: Cross multiply
   1,355.76x = 1,871.12 × 766.28
4. Step 4: Simplify right side
   1,355.76x = 1,433,801.83
5. Step 5: Solve for x
   x = 1,433,801.83/1,355.76
6. Step 6: Final answer
   x = 1,057.56