Finding the Fourth Proportional to 8,412.78, 12,619.59 and 3,218.25

Step by Step Solution

1. Step 1: Write the proportion equation
   8,412.78 : 12,619.59 = 3,218.25 : x
2. Step 2: Convert to fraction form
   8,412.78/12,619.59 = 3,218.25/x
3. Step 3: Cross multiply
   8,412.78x = 12,619.59 × 3,218.25
4. Step 4: Simplify right side
   8,412.78x = 40,612,995.52
5. Step 5: Solve for x
   x = 40,612,995.52/8,412.78
6. Step 6: Final answer
   x = 4,827.54