Finding the Fourth Proportional to 21,792, 30,072.96 and 12,960

Step by Step Solution

1. Step 1: Write the proportion equation
   21,792 : 30,072.96 = 12,960 : x
2. Step 2: Convert to fraction form
   21,792/30,072.96 = 12,960/x
3. Step 3: Cross multiply
   21,792x = 30,072.96 × 12,960
4. Step 4: Simplify right side
   21,792x = 389,745,561.60
5. Step 5: Solve for x
   x = 389,745,561.60/21,792
6. Step 6: Final answer
   x = 17,884.80