Finding the Fourth Proportional to 1,355.48, 1,870.48 and 766.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.48 : 1,870.48 = 766.20 : x
2. Step 2: Convert to fraction form
   1,355.48/1,870.48 = 766.20/x
3. Step 3: Cross multiply
   1,355.48x = 1,870.48 × 766.20
4. Step 4: Simplify right side
   1,355.48x = 1,433,161.78
5. Step 5: Solve for x
   x = 1,433,161.78/1,355.48
6. Step 6: Final answer
   x = 1,057.31