Finding the Fourth Proportional to 5,398.67, 8,078.74 and 3,919.61

Step by Step Solution

1. Step 1: Write the proportion equation
   5,398.67 : 8,078.74 = 3,919.61 : x
2. Step 2: Convert to fraction form
   5,398.67/8,078.74 = 3,919.61/x
3. Step 3: Cross multiply
   5,398.67x = 8,078.74 × 3,919.61
4. Step 4: Simplify right side
   5,398.67x = 31,665,510.09
5. Step 5: Solve for x
   x = 31,665,510.09/5,398.67
6. Step 6: Final answer
   x = 5,865.43