Finding the Fourth Proportional to 21,679.72, 29,921.82 and 12,607.89

Step by Step Solution

1. Step 1: Write the proportion equation
   21,679.72 : 29,921.82 = 12,607.89 : x
2. Step 2: Convert to fraction form
   21,679.72/29,921.82 = 12,607.89/x
3. Step 3: Cross multiply
   21,679.72x = 29,921.82 × 12,607.89
4. Step 4: Simplify right side
   21,679.72x = 377,250,926.59
5. Step 5: Solve for x
   x = 377,250,926.59/21,679.72
6. Step 6: Final answer
   x = 17,401.10