Finding the Fourth Proportional to 28,359.39, 42,545.15 and 8,639.53

Step by Step Solution

1. Step 1: Write the proportion equation
   28,359.39 : 42,545.15 = 8,639.53 : x
2. Step 2: Convert to fraction form
   28,359.39/42,545.15 = 8,639.53/x
3. Step 3: Cross multiply
   28,359.39x = 42,545.15 × 8,639.53
4. Step 4: Simplify right side
   28,359.39x = 367,570,099.78
5. Step 5: Solve for x
   x = 367,570,099.78/28,359.39
6. Step 6: Final answer
   x = 12,961.14