Finding the Fourth Proportional to 21,821.82, 30,112.71 and 12,868.86

Step by Step Solution

1. Step 1: Write the proportion equation
   21,821.82 : 30,112.71 = 12,868.86 : x
2. Step 2: Convert to fraction form
   21,821.82/30,112.71 = 12,868.86/x
3. Step 3: Cross multiply
   21,821.82x = 30,112.71 × 12,868.86
4. Step 4: Simplify right side
   21,821.82x = 387,516,249.21
5. Step 5: Solve for x
   x = 387,516,249.21/21,821.82
6. Step 6: Final answer
   x = 17,758.20