Finding the Fourth Proportional to 8,422.56, 12,635.76 and 2,578.80

Step by Step Solution

1. Step 1: Write the proportion equation
   8,422.56 : 12,635.76 = 2,578.80 : x
2. Step 2: Convert to fraction form
   8,422.56/12,635.76 = 2,578.80/x
3. Step 3: Cross multiply
   8,422.56x = 12,635.76 × 2,578.80
4. Step 4: Simplify right side
   8,422.56x = 32,585,097.89
5. Step 5: Solve for x
   x = 32,585,097.89/8,422.56
6. Step 6: Final answer
   x = 3,868.79