Finding the Fourth Proportional to 3,978.09, 5,491.59 and 2,486.97

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.09 : 5,491.59 = 2,486.97 : x
2. Step 2: Convert to fraction form
   3,978.09/5,491.59 = 2,486.97/x
3. Step 3: Cross multiply
   3,978.09x = 5,491.59 × 2,486.97
4. Step 4: Simplify right side
   3,978.09x = 13,657,419.58
5. Step 5: Solve for x
   x = 13,657,419.58/3,978.09
6. Step 6: Final answer
   x = 3,433.16