Finding the Fourth Proportional to 2,659.80, 3,990.41 and 2,615.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,659.80 : 3,990.41 = 2,615.76 : x
2. Step 2: Convert to fraction form
   2,659.80/3,990.41 = 2,615.76/x
3. Step 3: Cross multiply
   2,659.80x = 3,990.41 × 2,615.76
4. Step 4: Simplify right side
   2,659.80x = 10,437,941.78
5. Step 5: Solve for x
   x = 10,437,941.78/2,659.80
6. Step 6: Final answer
   x = 3,924.33