Finding the Fourth Proportional to 1,378.63, 1,902.67 and 789.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,378.63 : 1,902.67 = 789.25 : x
2. Step 2: Convert to fraction form
   1,378.63/1,902.67 = 789.25/x
3. Step 3: Cross multiply
   1,378.63x = 1,902.67 × 789.25
4. Step 4: Simplify right side
   1,378.63x = 1,501,682.30
5. Step 5: Solve for x
   x = 1,501,682.30/1,378.63
6. Step 6: Final answer
   x = 1,089.26