Finding the Fourth Proportional to 21,888.20, 30,205.83 and 12,456.76

Step by Step Solution

1. Step 1: Write the proportion equation
   21,888.20 : 30,205.83 = 12,456.76 : x
2. Step 2: Convert to fraction form
   21,888.20/30,205.83 = 12,456.76/x
3. Step 3: Cross multiply
   21,888.20x = 30,205.83 × 12,456.76
4. Step 4: Simplify right side
   21,888.20x = 376,266,623.88
5. Step 5: Solve for x
   x = 376,266,623.88/21,888.20
6. Step 6: Final answer
   x = 17,190.39