Finding the Fourth Proportional to 21,870.48, 30,186.20 and 13,906.48

Step by Step Solution

1. Step 1: Write the proportion equation
   21,870.48 : 30,186.20 = 13,906.48 : x
2. Step 2: Convert to fraction form
   21,870.48/30,186.20 = 13,906.48/x
3. Step 3: Cross multiply
   21,870.48x = 30,186.20 × 13,906.48
4. Step 4: Simplify right side
   21,870.48x = 419,783,786.58
5. Step 5: Solve for x
   x = 419,783,786.58/21,870.48
6. Step 6: Final answer
   x = 19,194.08