Finding the Fourth Proportional to 20,787.42, 31,170.17 and 14,215.49

Step by Step Solution

1. Step 1: Write the proportion equation
   20,787.42 : 31,170.17 = 14,215.49 : x
2. Step 2: Convert to fraction form
   20,787.42/31,170.17 = 14,215.49/x
3. Step 3: Cross multiply
   20,787.42x = 31,170.17 × 14,215.49
4. Step 4: Simplify right side
   20,787.42x = 443,099,013.01
5. Step 5: Solve for x
   x = 443,099,013.01/20,787.42
6. Step 6: Final answer
   x = 21,315.73