1. The sum of the internal angles of the triangle is 180. Because radian ratio is the ratio of chord included angle, an equation can be set up to solve it. That is, ∠c:∠a:∠b=3: 1:2, so ∠ C = 90. So △ABC is a right triangle.

2. The question means that △ABC is an equilateral triangle. So AB=BC=AC, so all △AOB equals △BOC equals △AOC, so the triangles are equal.