Finding the Fourth Proportional to 21,147.87, 31,721.71 and 5,353.05

Step by Step Solution

1. Step 1: Write the proportion equation
   21,147.87 : 31,721.71 = 5,353.05 : x
2. Step 2: Convert to fraction form
   21,147.87/31,721.71 = 5,353.05/x
3. Step 3: Cross multiply
   21,147.87x = 31,721.71 × 5,353.05
4. Step 4: Simplify right side
   21,147.87x = 169,807,899.72
5. Step 5: Solve for x
   x = 169,807,899.72/21,147.87
6. Step 6: Final answer
   x = 8,029.55