Finding the Fourth Proportional to 5,087.25, 7,631.28 and 1,389.78

Step by Step Solution

1. Step 1: Write the proportion equation
   5,087.25 : 7,631.28 = 1,389.78 : x
2. Step 2: Convert to fraction form
   5,087.25/7,631.28 = 1,389.78/x
3. Step 3: Cross multiply
   5,087.25x = 7,631.28 × 1,389.78
4. Step 4: Simplify right side
   5,087.25x = 10,605,800.32
5. Step 5: Solve for x
   x = 10,605,800.32/5,087.25
6. Step 6: Final answer
   x = 2,084.78