Finding the Fourth Proportional to 3,978.02, 5,485.39 and 2,485.39

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.02 : 5,485.39 = 2,485.39 : x
2. Step 2: Convert to fraction form
   3,978.02/5,485.39 = 2,485.39/x
3. Step 3: Cross multiply
   3,978.02x = 5,485.39 × 2,485.39
4. Step 4: Simplify right side
   3,978.02x = 13,633,321.03
5. Step 5: Solve for x
   x = 13,633,321.03/3,978.02
6. Step 6: Final answer
   x = 3,427.17