Finding the Fourth Proportional to 21,789.45, 30,071.48 and 12,839.73

Step by Step Solution

1. Step 1: Write the proportion equation
   21,789.45 : 30,071.48 = 12,839.73 : x
2. Step 2: Convert to fraction form
   21,789.45/30,071.48 = 12,839.73/x
3. Step 3: Cross multiply
   21,789.45x = 30,071.48 × 12,839.73
4. Step 4: Simplify right side
   21,789.45x = 386,109,619.70
5. Step 5: Solve for x
   x = 386,109,619.70/21,789.45
6. Step 6: Final answer
   x = 17,720.03