Finding the Fourth Proportional to 21,636.72, 29,858.90 and 12,684.47

Step by Step Solution

1. Step 1: Write the proportion equation
   21,636.72 : 29,858.90 = 12,684.47 : x
2. Step 2: Convert to fraction form
   21,636.72/29,858.90 = 12,684.47/x
3. Step 3: Cross multiply
   21,636.72x = 29,858.90 × 12,684.47
4. Step 4: Simplify right side
   21,636.72x = 378,744,108.57
5. Step 5: Solve for x
   x = 378,744,108.57/21,636.72
6. Step 6: Final answer
   x = 17,504.69