Finding the Fourth Proportional to 3,991.56, 5,978.16 and 3,853.20

Step by Step Solution

1. Step 1: Write the proportion equation
   3,991.56 : 5,978.16 = 3,853.20 : x
2. Step 2: Convert to fraction form
   3,991.56/5,978.16 = 3,853.20/x
3. Step 3: Cross multiply
   3,991.56x = 5,978.16 × 3,853.20
4. Step 4: Simplify right side
   3,991.56x = 23,035,046.11
5. Step 5: Solve for x
   x = 23,035,046.11/3,991.56
6. Step 6: Final answer
   x = 5,770.94