Finding the Fourth Proportional to 3,902.76, 5,388.80 and 2,578.28

Step by Step Solution

1. Step 1: Write the proportion equation
   3,902.76 : 5,388.80 = 2,578.28 : x
2. Step 2: Convert to fraction form
   3,902.76/5,388.80 = 2,578.28/x
3. Step 3: Cross multiply
   3,902.76x = 5,388.80 × 2,578.28
4. Step 4: Simplify right side
   3,902.76x = 13,893,795.43
5. Step 5: Solve for x
   x = 13,893,795.43/3,902.76
6. Step 6: Final answer
   x = 3,559.99