Finding the Fourth Proportional to 1,355.28, 1,870.32 and 765.84

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.28 : 1,870.32 = 765.84 : x
2. Step 2: Convert to fraction form
   1,355.28/1,870.32 = 765.84/x
3. Step 3: Cross multiply
   1,355.28x = 1,870.32 × 765.84
4. Step 4: Simplify right side
   1,355.28x = 1,432,365.87
5. Step 5: Solve for x
   x = 1,432,365.87/1,355.28
6. Step 6: Final answer
   x = 1,056.88