Finding the Fourth Proportional to 3,811.78, 5,258.72 and 2,485

Step by Step Solution

1. Step 1: Write the proportion equation
   3,811.78 : 5,258.72 = 2,485 : x
2. Step 2: Convert to fraction form
   3,811.78/5,258.72 = 2,485/x
3. Step 3: Cross multiply
   3,811.78x = 5,258.72 × 2,485
4. Step 4: Simplify right side
   3,811.78x = 13,067,919.20
5. Step 5: Solve for x
   x = 13,067,919.20/3,811.78
6. Step 6: Final answer
   x = 3,428.30