Finding the Fourth Proportional to 21,821.32, 30,111.98 and 12,868.40

Step by Step Solution

1. Step 1: Write the proportion equation
   21,821.32 : 30,111.98 = 12,868.40 : x
2. Step 2: Convert to fraction form
   21,821.32/30,111.98 = 12,868.40/x
3. Step 3: Cross multiply
   21,821.32x = 30,111.98 × 12,868.40
4. Step 4: Simplify right side
   21,821.32x = 387,493,003.43
5. Step 5: Solve for x
   x = 387,493,003.43/21,821.32
6. Step 6: Final answer
   x = 17,757.54