Finding the Fourth Proportional to 21,309.37, 29,409.78 and 12,238.30

Step by Step Solution

1. Step 1: Write the proportion equation
   21,309.37 : 29,409.78 = 12,238.30 : x
2. Step 2: Convert to fraction form
   21,309.37/29,409.78 = 12,238.30/x
3. Step 3: Cross multiply
   21,309.37x = 29,409.78 × 12,238.30
4. Step 4: Simplify right side
   21,309.37x = 359,925,710.57
5. Step 5: Solve for x
   x = 359,925,710.57/21,309.37
6. Step 6: Final answer
   x = 16,890.49