Finding the Fourth Proportional to 21,013.73, 31,521.68 and 5,431.49

Step by Step Solution

1. Step 1: Write the proportion equation
   21,013.73 : 31,521.68 = 5,431.49 : x
2. Step 2: Convert to fraction form
   21,013.73/31,521.68 = 5,431.49/x
3. Step 3: Cross multiply
   21,013.73x = 31,521.68 × 5,431.49
4. Step 4: Simplify right side
   21,013.73x = 171,209,662.55
5. Step 5: Solve for x
   x = 171,209,662.55/21,013.73
6. Step 6: Final answer
   x = 8,147.51