Finding the Fourth Proportional to 21,018.79, 29,017.90 and 13,869.33

Step by Step Solution

1. Step 1: Write the proportion equation
   21,018.79 : 29,017.90 = 13,869.33 : x
2. Step 2: Convert to fraction form
   21,018.79/29,017.90 = 13,869.33/x
3. Step 3: Cross multiply
   21,018.79x = 29,017.90 × 13,869.33
4. Step 4: Simplify right side
   21,018.79x = 402,458,661.51
5. Step 5: Solve for x
   x = 402,458,661.51/21,018.79
6. Step 6: Final answer
   x = 19,147.56