Finding the Fourth Proportional to 1,355.31, 1,870.11 and 765.75

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.31 : 1,870.11 = 765.75 : x
2. Step 2: Convert to fraction form
   1,355.31/1,870.11 = 765.75/x
3. Step 3: Cross multiply
   1,355.31x = 1,870.11 × 765.75
4. Step 4: Simplify right side
   1,355.31x = 1,432,036.73
5. Step 5: Solve for x
   x = 1,432,036.73/1,355.31
6. Step 6: Final answer
   x = 1,056.61