Finding the Fourth Proportional to 12,399.72, 17,105.24 and 7,918.76

Step by Step Solution

1. Step 1: Write the proportion equation
   12,399.72 : 17,105.24 = 7,918.76 : x
2. Step 2: Convert to fraction form
   12,399.72/17,105.24 = 7,918.76/x
3. Step 3: Cross multiply
   12,399.72x = 17,105.24 × 7,918.76
4. Step 4: Simplify right side
   12,399.72x = 135,452,290.30
5. Step 5: Solve for x
   x = 135,452,290.30/12,399.72
6. Step 6: Final answer
   x = 10,923.82