Finding the Fourth Proportional to 12,478.95, 18,715.89 and 4,578.78

Step by Step Solution

1. Step 1: Write the proportion equation
   12,478.95 : 18,715.89 = 4,578.78 : x
2. Step 2: Convert to fraction form
   12,478.95/18,715.89 = 4,578.78/x
3. Step 3: Cross multiply
   12,478.95x = 18,715.89 × 4,578.78
4. Step 4: Simplify right side
   12,478.95x = 85,695,942.81
5. Step 5: Solve for x
   x = 85,695,942.81/12,478.95
6. Step 6: Final answer
   x = 6,867.24