Finding the Fourth Proportional to 21,826.79, 30,117.30 and 12,876.06

Step by Step Solution

1. Step 1: Write the proportion equation
   21,826.79 : 30,117.30 = 12,876.06 : x
2. Step 2: Convert to fraction form
   21,826.79/30,117.30 = 12,876.06/x
3. Step 3: Cross multiply
   21,826.79x = 30,117.30 × 12,876.06
4. Step 4: Simplify right side
   21,826.79x = 387,792,298.92
5. Step 5: Solve for x
   x = 387,792,298.92/21,826.79
6. Step 6: Final answer
   x = 17,766.80