Finding the Fourth Proportional to 21,871.51, 30,185.10 and 12,311.69

Step by Step Solution

1. Step 1: Write the proportion equation
   21,871.51 : 30,185.10 = 12,311.69 : x
2. Step 2: Convert to fraction form
   21,871.51/30,185.10 = 12,311.69/x
3. Step 3: Cross multiply
   21,871.51x = 30,185.10 × 12,311.69
4. Step 4: Simplify right side
   21,871.51x = 371,629,593.82
5. Step 5: Solve for x
   x = 371,629,593.82/21,871.51
6. Step 6: Final answer
   x = 16,991.49