Finding the Fourth Proportional to 21,960.84, 30,298.48 and 12,399.60

Step by Step Solution

1. Step 1: Write the proportion equation
   21,960.84 : 30,298.48 = 12,399.60 : x
2. Step 2: Convert to fraction form
   21,960.84/30,298.48 = 12,399.60/x
3. Step 3: Cross multiply
   21,960.84x = 30,298.48 × 12,399.60
4. Step 4: Simplify right side
   21,960.84x = 375,689,032.61
5. Step 5: Solve for x
   x = 375,689,032.61/21,960.84
6. Step 6: Final answer
   x = 17,107.23