Finding the Fourth Proportional to 3,978.79, 5,490.38 and 2,185.97

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.79 : 5,490.38 = 2,185.97 : x
2. Step 2: Convert to fraction form
   3,978.79/5,490.38 = 2,185.97/x
3. Step 3: Cross multiply
   3,978.79x = 5,490.38 × 2,185.97
4. Step 4: Simplify right side
   3,978.79x = 12,001,795.04
5. Step 5: Solve for x
   x = 12,001,795.04/3,978.79
6. Step 6: Final answer
   x = 3,016.45