Finding the Fourth Proportional to 21,858, 30,164.04 and 12,427.20

Step by Step Solution

1. Step 1: Write the proportion equation
   21,858 : 30,164.04 = 12,427.20 : x
2. Step 2: Convert to fraction form
   21,858/30,164.04 = 12,427.20/x
3. Step 3: Cross multiply
   21,858x = 30,164.04 × 12,427.20
4. Step 4: Simplify right side
   21,858x = 374,854,557.89
5. Step 5: Solve for x
   x = 374,854,557.89/21,858
6. Step 6: Final answer
   x = 17,149.54