Finding the Fourth Proportional to 21,013.25, 31,498.61 and 13,622.40

Step by Step Solution

1. Step 1: Write the proportion equation
   21,013.25 : 31,498.61 = 13,622.40 : x
2. Step 2: Convert to fraction form
   21,013.25/31,498.61 = 13,622.40/x
3. Step 3: Cross multiply
   21,013.25x = 31,498.61 × 13,622.40
4. Step 4: Simplify right side
   21,013.25x = 429,086,596.75
5. Step 5: Solve for x
   x = 429,086,596.75/21,013.25
6. Step 6: Final answer
   x = 20,419.82