Finding the Fourth Proportional to 12,856.82, 17,743.73 and 7,821.40

Step by Step Solution

1. Step 1: Write the proportion equation
   12,856.82 : 17,743.73 = 7,821.40 : x
2. Step 2: Convert to fraction form
   12,856.82/17,743.73 = 7,821.40/x
3. Step 3: Cross multiply
   12,856.82x = 17,743.73 × 7,821.40
4. Step 4: Simplify right side
   12,856.82x = 138,780,809.82
5. Step 5: Solve for x
   x = 138,780,809.82/12,856.82
6. Step 6: Final answer
   x = 10,794.33