Dear student,

The given vertices are = (3,-1,2) , (1,-1,2) and (4,-2,1) and there is a direct formula to calculate the area of the triangle.

The determinant = 1/2 |x1 x2 X3|

|x4 x5 x6|

|x7 x8 x9|

After evaluation this determinant you will get the result.

There is one more formula but that is difficult to memorize so it's better to evaluate this in determinant form. Actually after evaluating this determinant you would get the same formula.