Finding the Fourth Proportional to 21,308.72, 31,967.70 and 8,161.10

Step by Step Solution

1. Step 1: Write the proportion equation
   21,308.72 : 31,967.70 = 8,161.10 : x
2. Step 2: Convert to fraction form
   21,308.72/31,967.70 = 8,161.10/x
3. Step 3: Cross multiply
   21,308.72x = 31,967.70 × 8,161.10
4. Step 4: Simplify right side
   21,308.72x = 260,891,436.63
5. Step 5: Solve for x
   x = 260,891,436.63/21,308.72
6. Step 6: Final answer
   x = 12,243.41