The figure shows the arrangement of desks in a classroom. Ashima,Bharti,and Camella are seated at $A (3, 1)$,$B (6, 4)$,and $C (8, 6)$ respectively. Do you think they are seated in a line? Give reasons for your answer.

(N/A) Using the distance formula,we have:
$AB = \sqrt{(6-3)^{2} + (4-1)^{2}} = \sqrt{3^{2} + 3^{2}} = \sqrt{9 + 9} = \sqrt{18} = 3\sqrt{2}$
$BC = \sqrt{(8-6)^{2} + (6-4)^{2}} = \sqrt{2^{2} + 2^{2}} = \sqrt{4 + 4} = \sqrt{8} = 2\sqrt{2}$
$AC = \sqrt{(8-3)^{2} + (6-1)^{2}} = \sqrt{5^{2} + 5^{2}} = \sqrt{25 + 25} = \sqrt{50} = 5\sqrt{2}$
Since $AB + BC = 3\sqrt{2} + 2\sqrt{2} = 5\sqrt{2} = AC$,the sum of the distances $AB$ and $BC$ is equal to the distance $AC$. Therefore,the points $A$,$B$,and $C$ are collinear,which means they are seated in a line.