Finding the Fourth Proportional to 21,258.72, 29,329.20 and 12,872.16

Step by Step Solution

1. Step 1: Write the proportion equation
   21,258.72 : 29,329.20 = 12,872.16 : x
2. Step 2: Convert to fraction form
   21,258.72/29,329.20 = 12,872.16/x
3. Step 3: Cross multiply
   21,258.72x = 29,329.20 × 12,872.16
4. Step 4: Simplify right side
   21,258.72x = 377,530,155.07
5. Step 5: Solve for x
   x = 377,530,155.07/21,258.72
6. Step 6: Final answer
   x = 17,758.84