Finding the Fourth Proportional to 21,606.79, 29,819.78 and 13,648.63

Step by Step Solution

1. Step 1: Write the proportion equation
   21,606.79 : 29,819.78 = 13,648.63 : x
2. Step 2: Convert to fraction form
   21,606.79/29,819.78 = 13,648.63/x
3. Step 3: Cross multiply
   21,606.79x = 29,819.78 × 13,648.63
4. Step 4: Simplify right side
   21,606.79x = 406,999,143.90
5. Step 5: Solve for x
   x = 406,999,143.90/21,606.79
6. Step 6: Final answer
   x = 18,836.63