Finding the Fourth Proportional to 21,871.90, 30,185.88 and 12,315.37

Step by Step Solution

1. Step 1: Write the proportion equation
   21,871.90 : 30,185.88 = 12,315.37 : x
2. Step 2: Convert to fraction form
   21,871.90/30,185.88 = 12,315.37/x
3. Step 3: Cross multiply
   21,871.90x = 30,185.88 × 12,315.37
4. Step 4: Simplify right side
   21,871.90x = 371,750,280.98
5. Step 5: Solve for x
   x = 371,750,280.98/21,871.90
6. Step 6: Final answer
   x = 16,996.71