Finding the Fourth Proportional to 21,426.13, 29,561.23 and 13,878.25

Step by Step Solution

1. Step 1: Write the proportion equation
   21,426.13 : 29,561.23 = 13,878.25 : x
2. Step 2: Convert to fraction form
   21,426.13/29,561.23 = 13,878.25/x
3. Step 3: Cross multiply
   21,426.13x = 29,561.23 × 13,878.25
4. Step 4: Simplify right side
   21,426.13x = 410,258,140.25
5. Step 5: Solve for x
   x = 410,258,140.25/21,426.13
6. Step 6: Final answer
   x = 19,147.56