The coordinates of the three points A,B,C on the plane are (-5,-5),(-2,-1) and(-1,-2),respectively,the triangle ABC is ( )A.a right triangle B.an isosceles triangleC.an equilateral triangle D.an obtuse triangle
(-1,-2),respectively,the triangle ABC is ( )A.a right triangle B.an isosceles triangleC.an equilateral triangle D.an obtuse triangle
A.a right triangle B.an isosceles triangleC.an equilateral triangle D.an obtuse triangle
C.an equilateral triangle D.an obtuse triangle