Finding the Fourth Proportional to 21,645.36, 29,872.72 and 13,145.52

Step by Step Solution

1. Step 1: Write the proportion equation
   21,645.36 : 29,872.72 = 13,145.52 : x
2. Step 2: Convert to fraction form
   21,645.36/29,872.72 = 13,145.52/x
3. Step 3: Cross multiply
   21,645.36x = 29,872.72 × 13,145.52
4. Step 4: Simplify right side
   21,645.36x = 392,692,438.21
5. Step 5: Solve for x
   x = 392,692,438.21/21,645.36
6. Step 6: Final answer
   x = 18,142.11