関連ワード:  a triangle abc is drawn to circumscribe    a triangle abc    a triangle abc is drawn to circumscribe a circle    a triangle abc is drawn to    a triangle abc lying in the first quadrant    a triangle abc is right angled at a    a triangle abc is formed by the lines 2x-3y-6=0    a triangle abc with vertices a(-1 0)    a triangle abc is right angled at b    a triangle abc is drawn to circum