Finding the Fourth Proportional to 9,405.05, 12,981.30 and 5,428.55

Step by Step Solution

1. Step 1: Write the proportion equation
   9,405.05 : 12,981.30 = 5,428.55 : x
2. Step 2: Convert to fraction form
   9,405.05/12,981.30 = 5,428.55/x
3. Step 3: Cross multiply
   9,405.05x = 12,981.30 × 5,428.55
4. Step 4: Simplify right side
   9,405.05x = 70,469,636.12
5. Step 5: Solve for x
   x = 70,469,636.12/9,405.05
6. Step 6: Final answer
   x = 7,492.74