Finding the Fourth Proportional to 12,939.12, 17,856.20 and 10,109.76

Step by Step Solution

1. Step 1: Write the proportion equation
   12,939.12 : 17,856.20 = 10,109.76 : x
2. Step 2: Convert to fraction form
   12,939.12/17,856.20 = 10,109.76/x
3. Step 3: Cross multiply
   12,939.12x = 17,856.20 × 10,109.76
4. Step 4: Simplify right side
   12,939.12x = 180,521,896.51
5. Step 5: Solve for x
   x = 180,521,896.51/12,939.12
6. Step 6: Final answer
   x = 13,951.64