Finding the Fourth Proportional to 20,621.12, 30,910.55 and 8,136.10

Step by Step Solution

1. Step 1: Write the proportion equation
   20,621.12 : 30,910.55 = 8,136.10 : x
2. Step 2: Convert to fraction form
   20,621.12/30,910.55 = 8,136.10/x
3. Step 3: Cross multiply
   20,621.12x = 30,910.55 × 8,136.10
4. Step 4: Simplify right side
   20,621.12x = 251,491,171.30
5. Step 5: Solve for x
   x = 251,491,171.30/20,621.12
6. Step 6: Final answer
   x = 12,195.81