Finding the Fourth Proportional to 1,378.57, 1,902.53 and 789.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,378.57 : 1,902.53 = 789.15 : x
2. Step 2: Convert to fraction form
   1,378.57/1,902.53 = 789.15/x
3. Step 3: Cross multiply
   1,378.57x = 1,902.53 × 789.15
4. Step 4: Simplify right side
   1,378.57x = 1,501,376.39
5. Step 5: Solve for x
   x = 1,501,376.39/1,378.57
6. Step 6: Final answer
   x = 1,089.08