Finding the Fourth Proportional to 12,878.81, 17,768.59 and 7,212.71

Step by Step Solution

1. Step 1: Write the proportion equation
   12,878.81 : 17,768.59 = 7,212.71 : x
2. Step 2: Convert to fraction form
   12,878.81/17,768.59 = 7,212.71/x
3. Step 3: Cross multiply
   12,878.81x = 17,768.59 × 7,212.71
4. Step 4: Simplify right side
   12,878.81x = 128,159,686.78
5. Step 5: Solve for x
   x = 128,159,686.78/12,878.81
6. Step 6: Final answer
   x = 9,951.21