Finding the Fourth Proportional to 21,819.28, 30,111.78 and 12,872.02

Step by Step Solution

1. Step 1: Write the proportion equation
   21,819.28 : 30,111.78 = 12,872.02 : x
2. Step 2: Convert to fraction form
   21,819.28/30,111.78 = 12,872.02/x
3. Step 3: Cross multiply
   21,819.28x = 30,111.78 × 12,872.02
4. Step 4: Simplify right side
   21,819.28x = 387,599,434.40
5. Step 5: Solve for x
   x = 387,599,434.40/21,819.28
6. Step 6: Final answer
   x = 17,764.08