Finding the Fourth Proportional to 20,718.21, 31,104.42 and 12,300.09

Step by Step Solution

1. Step 1: Write the proportion equation
   20,718.21 : 31,104.42 = 12,300.09 : x
2. Step 2: Convert to fraction form
   20,718.21/31,104.42 = 12,300.09/x
3. Step 3: Cross multiply
   20,718.21x = 31,104.42 × 12,300.09
4. Step 4: Simplify right side
   20,718.21x = 382,587,165.40
5. Step 5: Solve for x
   x = 382,587,165.40/20,718.21
6. Step 6: Final answer
   x = 18,466.23