Finding the Fourth Proportional to 3,915.50, 5,406.90 and 2,520.68

Step by Step Solution

1. Step 1: Write the proportion equation
   3,915.50 : 5,406.90 = 2,520.68 : x
2. Step 2: Convert to fraction form
   3,915.50/5,406.90 = 2,520.68/x
3. Step 3: Cross multiply
   3,915.50x = 5,406.90 × 2,520.68
4. Step 4: Simplify right side
   3,915.50x = 13,629,064.69
5. Step 5: Solve for x
   x = 13,629,064.69/3,915.50
6. Step 6: Final answer
   x = 3,480.80