Finding the Fourth Proportional to 21,150.72, 31,691.52 and 13,334.40

Step by Step Solution

1. Step 1: Write the proportion equation
   21,150.72 : 31,691.52 = 13,334.40 : x
2. Step 2: Convert to fraction form
   21,150.72/31,691.52 = 13,334.40/x
3. Step 3: Cross multiply
   21,150.72x = 31,691.52 × 13,334.40
4. Step 4: Simplify right side
   21,150.72x = 422,587,404.29
5. Step 5: Solve for x
   x = 422,587,404.29/21,150.72
6. Step 6: Final answer
   x = 19,979.81