Finding the Fourth Proportional to 21,900.87, 30,225.56 and 13,408.71

Step by Step Solution

1. Step 1: Write the proportion equation
   21,900.87 : 30,225.56 = 13,408.71 : x
2. Step 2: Convert to fraction form
   21,900.87/30,225.56 = 13,408.71/x
3. Step 3: Cross multiply
   21,900.87x = 30,225.56 × 13,408.71
4. Step 4: Simplify right side
   21,900.87x = 405,285,768.63
5. Step 5: Solve for x
   x = 405,285,768.63/21,900.87
6. Step 6: Final answer
   x = 18,505.46