Finding the Fourth Proportional to 3,986.78, 5,501.51 and 2,218.34

Step by Step Solution

1. Step 1: Write the proportion equation
   3,986.78 : 5,501.51 = 2,218.34 : x
2. Step 2: Convert to fraction form
   3,986.78/5,501.51 = 2,218.34/x
3. Step 3: Cross multiply
   3,986.78x = 5,501.51 × 2,218.34
4. Step 4: Simplify right side
   3,986.78x = 12,204,208.60
5. Step 5: Solve for x
   x = 12,204,208.60/3,986.78
6. Step 6: Final answer
   x = 3,061.17