Finding the Fourth Proportional to 20,942.22, 28,890.63 and 12,868.55

Step by Step Solution

1. Step 1: Write the proportion equation
   20,942.22 : 28,890.63 = 12,868.55 : x
2. Step 2: Convert to fraction form
   20,942.22/28,890.63 = 12,868.55/x
3. Step 3: Cross multiply
   20,942.22x = 28,890.63 × 12,868.55
4. Step 4: Simplify right side
   20,942.22x = 371,780,516.69
5. Step 5: Solve for x
   x = 371,780,516.69/20,942.22
6. Step 6: Final answer
   x = 17,752.68