Finding the Fourth Proportional to 20,428.97, 30,636.09 and 7,278.71

Step by Step Solution

1. Step 1: Write the proportion equation
   20,428.97 : 30,636.09 = 7,278.71 : x
2. Step 2: Convert to fraction form
   20,428.97/30,636.09 = 7,278.71/x
3. Step 3: Cross multiply
   20,428.97x = 30,636.09 × 7,278.71
4. Step 4: Simplify right side
   20,428.97x = 222,991,061.46
5. Step 5: Solve for x
   x = 222,991,061.46/20,428.97
6. Step 6: Final answer
   x = 10,915.44