Finding the Fourth Proportional to 8,315.60, 11,478.78 and 5,664.47

Step by Step Solution

1. Step 1: Write the proportion equation
   8,315.60 : 11,478.78 = 5,664.47 : x
2. Step 2: Convert to fraction form
   8,315.60/11,478.78 = 5,664.47/x
3. Step 3: Cross multiply
   8,315.60x = 11,478.78 × 5,664.47
4. Step 4: Simplify right side
   8,315.60x = 65,021,147.55
5. Step 5: Solve for x
   x = 65,021,147.55/8,315.60
6. Step 6: Final answer
   x = 7,819.18