Finding the Fourth Proportional to 21,610.56, 29,802.72 and 13,638.96

Step by Step Solution

1. Step 1: Write the proportion equation
   21,610.56 : 29,802.72 = 13,638.96 : x
2. Step 2: Convert to fraction form
   21,610.56/29,802.72 = 13,638.96/x
3. Step 3: Cross multiply
   21,610.56x = 29,802.72 × 13,638.96
4. Step 4: Simplify right side
   21,610.56x = 406,478,105.97
5. Step 5: Solve for x
   x = 406,478,105.97/21,610.56
6. Step 6: Final answer
   x = 18,809.24