Finding the Fourth Proportional to 12,456.69, 17,188.83 and 7,420.20

Step by Step Solution

1. Step 1: Write the proportion equation
   12,456.69 : 17,188.83 = 7,420.20 : x
2. Step 2: Convert to fraction form
   12,456.69/17,188.83 = 7,420.20/x
3. Step 3: Cross multiply
   12,456.69x = 17,188.83 × 7,420.20
4. Step 4: Simplify right side
   12,456.69x = 127,544,556.37
5. Step 5: Solve for x
   x = 127,544,556.37/12,456.69
6. Step 6: Final answer
   x = 10,239.04