Finding the Fourth Proportional to 21,152.72, 31,694.52 and 13,336.40

Step by Step Solution

1. Step 1: Write the proportion equation
   21,152.72 : 31,694.52 = 13,336.40 : x
2. Step 2: Convert to fraction form
   21,152.72/31,694.52 = 13,336.40/x
3. Step 3: Cross multiply
   21,152.72x = 31,694.52 × 13,336.40
4. Step 4: Simplify right side
   21,152.72x = 422,690,796.53
5. Step 5: Solve for x
   x = 422,690,796.53/21,152.72
6. Step 6: Final answer
   x = 19,982.81