Finding the Fourth Proportional to 21,381.48, 29,505.24 and 13,428

Step by Step Solution

1. Step 1: Write the proportion equation
   21,381.48 : 29,505.24 = 13,428 : x
2. Step 2: Convert to fraction form
   21,381.48/29,505.24 = 13,428/x
3. Step 3: Cross multiply
   21,381.48x = 29,505.24 × 13,428
4. Step 4: Simplify right side
   21,381.48x = 396,196,362.72
5. Step 5: Solve for x
   x = 396,196,362.72/21,381.48
6. Step 6: Final answer
   x = 18,529.88