Finding the Fourth Proportional to 9,420.05, 12,999.60 and 5,171.10

Step by Step Solution

1. Step 1: Write the proportion equation
   9,420.05 : 12,999.60 = 5,171.10 : x
2. Step 2: Convert to fraction form
   9,420.05/12,999.60 = 5,171.10/x
3. Step 3: Cross multiply
   9,420.05x = 12,999.60 × 5,171.10
4. Step 4: Simplify right side
   9,420.05x = 67,222,231.56
5. Step 5: Solve for x
   x = 67,222,231.56/9,420.05
6. Step 6: Final answer
   x = 7,136.08