Finding the Fourth Proportional to 21,271.98, 31,900.78 and 7,942.21

Step by Step Solution

1. Step 1: Write the proportion equation
   21,271.98 : 31,900.78 = 7,942.21 : x
2. Step 2: Convert to fraction form
   21,271.98/31,900.78 = 7,942.21/x
3. Step 3: Cross multiply
   21,271.98x = 31,900.78 × 7,942.21
4. Step 4: Simplify right side
   21,271.98x = 253,362,693.92
5. Step 5: Solve for x
   x = 253,362,693.92/21,271.98
6. Step 6: Final answer
   x = 11,910.63