Finding the Fourth Proportional to 3,978.61, 5,965.89 and 2,105.53

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.61 : 5,965.89 = 2,105.53 : x
2. Step 2: Convert to fraction form
   3,978.61/5,965.89 = 2,105.53/x
3. Step 3: Cross multiply
   3,978.61x = 5,965.89 × 2,105.53
4. Step 4: Simplify right side
   3,978.61x = 12,561,360.37
5. Step 5: Solve for x
   x = 12,561,360.37/3,978.61
6. Step 6: Final answer
   x = 3,157.22