  # What Types of Triangles There Are

A triangle is a polygon that has 3 angles, and 3 line segments joined end to end. Thus, we can say that a triangle is a polygon, which has 3 sides, 3 angles, 3 vertices, and the sum of all 3 angles of any triangle equals 180°. Sides and angles define the type of triangle.

5-Minute Crafts would like to tell you about what types of triangles there are. In the bonus section, we’ll recall some terms from our school geometry course.

### Types of triangles by angle

• right triangle has one angle equal to 90°.
• An acute triangle has 3 angles that are all less than 90°.
• An obtuse triangle has one angle that is more than 90°.

### Types of triangles by side

• All 3 sides of an equilateral triangle are equal. Since all 3 sides have the same length, all 3 angles are equal too. Each angle of an equilateral triangle is 60°.
• 2 sides out of 3 on an isosceles triangle have the same length.
• All 3 sides of a scalene triangle have different lengths.

### Bonus: Terms that describe the elements of an triangle

• The legs are the sides in a right triangle that form its right angle (90°).
• The hypotenuse of a right triangle is the side opposite its right angle.
• The median of a triangle is a line segment that joins one of its vertices with the center of the opposite side.
• The altitude of a triangle, or height, is a line from a vertex to the opposite side, that is perpendicular to that side.
• An angle bisector of an angle of a triangle divides the opposite side into 2 segments that are proportional to the other 2 sides of the triangle.
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