Finding the Fourth Proportional to 3,986.75, 5,978.29 and 1,212.81

Step by Step Solution

1. Step 1: Write the proportion equation
   3,986.75 : 5,978.29 = 1,212.81 : x
2. Step 2: Convert to fraction form
   3,986.75/5,978.29 = 1,212.81/x
3. Step 3: Cross multiply
   3,986.75x = 5,978.29 × 1,212.81
4. Step 4: Simplify right side
   3,986.75x = 7,250,529.89
5. Step 5: Solve for x
   x = 7,250,529.89/3,986.75
6. Step 6: Final answer
   x = 1,818.66