Finding the Fourth Proportional to 21,456.18, 29,611.17 and 13,505.22

Step by Step Solution

1. Step 1: Write the proportion equation
   21,456.18 : 29,611.17 = 13,505.22 : x
2. Step 2: Convert to fraction form
   21,456.18/29,611.17 = 13,505.22/x
3. Step 3: Cross multiply
   21,456.18x = 29,611.17 × 13,505.22
4. Step 4: Simplify right side
   21,456.18x = 399,905,365.31
5. Step 5: Solve for x
   x = 399,905,365.31/21,456.18
6. Step 6: Final answer
   x = 18,638.24