The teacher put a piece of cardboard cut into a triangle, triangle right triangle, no installation on the Board and ask students what kind of image is a right triangle, because anything.
Teachers put a sheet of cardboard cut into an equilateral triangle, scalene triangle, triangle mounted on the board and ask students what shape triangle that is why.
The teacher brought a piece of cardboard cut is an equilateral triangle scalene triangle, triangle angle, scene, stick on the board and ask students what shape is a right-angled triangle Why