Finding the Fourth Proportional to 1,355.69, 1,870.86 and 766.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.69 : 1,870.86 = 766.28 : x
2. Step 2: Convert to fraction form
   1,355.69/1,870.86 = 766.28/x
3. Step 3: Cross multiply
   1,355.69x = 1,870.86 × 766.28
4. Step 4: Simplify right side
   1,355.69x = 1,433,602.60
5. Step 5: Solve for x
   x = 1,433,602.60/1,355.69
6. Step 6: Final answer
   x = 1,057.47