Finding the Fourth Proportional to 2,578.86, 3,865.59 and 1,961.27

Step by Step Solution

1. Step 1: Write the proportion equation
   2,578.86 : 3,865.59 = 1,961.27 : x
2. Step 2: Convert to fraction form
   2,578.86/3,865.59 = 1,961.27/x
3. Step 3: Cross multiply
   2,578.86x = 3,865.59 × 1,961.27
4. Step 4: Simplify right side
   2,578.86x = 7,581,446.37
5. Step 5: Solve for x
   x = 7,581,446.37/2,578.86
6. Step 6: Final answer
   x = 2,939.84