Finding the Fourth Proportional to 21,829.30, 30,117.42 and 12,879.81

Step by Step Solution

1. Step 1: Write the proportion equation
   21,829.30 : 30,117.42 = 12,879.81 : x
2. Step 2: Convert to fraction form
   21,829.30/30,117.42 = 12,879.81/x
3. Step 3: Cross multiply
   21,829.30x = 30,117.42 × 12,879.81
4. Step 4: Simplify right side
   21,829.30x = 387,906,647.29
5. Step 5: Solve for x
   x = 387,906,647.29/21,829.30
6. Step 6: Final answer
   x = 17,770.00