Finding the Fourth Proportional to 2,615.78, 3,609.61 and 2,406.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,615.78 : 3,609.61 = 2,406.80 : x
2. Step 2: Convert to fraction form
   2,615.78/3,609.61 = 2,406.80/x
3. Step 3: Cross multiply
   2,615.78x = 3,609.61 × 2,406.80
4. Step 4: Simplify right side
   2,615.78x = 8,687,579.27
5. Step 5: Solve for x
   x = 8,687,579.27/2,615.78
6. Step 6: Final answer
   x = 3,321.23