Finding the Fourth Proportional to 39,028.72, 53,859.21 and 21,123.34

Step by Step Solution

1. Step 1: Write the proportion equation
   39,028.72 : 53,859.21 = 21,123.34 : x
2. Step 2: Convert to fraction form
   39,028.72/53,859.21 = 21,123.34/x
3. Step 3: Cross multiply
   39,028.72x = 53,859.21 × 21,123.34
4. Step 4: Simplify right side
   39,028.72x = 1,137,686,404.96
5. Step 5: Solve for x
   x = 1,137,686,404.96/39,028.72
6. Step 6: Final answer
   x = 29,149.98