Finding the Fourth Proportional to 21,390.49, 32,091.20 and 8,906.37

Step by Step Solution

1. Step 1: Write the proportion equation
   21,390.49 : 32,091.20 = 8,906.37 : x
2. Step 2: Convert to fraction form
   21,390.49/32,091.20 = 8,906.37/x
3. Step 3: Cross multiply
   21,390.49x = 32,091.20 × 8,906.37
4. Step 4: Simplify right side
   21,390.49x = 285,816,100.94
5. Step 5: Solve for x
   x = 285,816,100.94/21,390.49
6. Step 6: Final answer
   x = 13,361.83