1, acute angle: an angle greater than 0 and less than 90 is called an acute angle.

2. Right angle: An angle equal to 90 is called a right angle.

3. Oblique angle: An angle greater than 90 and less than180 is called obtuse angle.

4. Right angle: The angle equal to 180 is called right angle.

5. Principal angle: the value greater than 180 and less than 360 is called the principal angle.

Divide by edge

1, equilateral triangle; An equilateral triangle is mathematically defined as a triangle with three unequal sides.

2, isosceles triangle; An isosceles triangle refers to a triangle with two equal sides, which are called the waist of the triangle. In an isosceles triangle, two equal sides are called waist and the other side is called bottom. The angle between the two waists is called the top angle, and the angle between the waist and the bottom edge is called the bottom angle.