- For other meanings, such as the musical instrument that is also called a "triangle", see triangle (disambiguation).
A triangle is a shape or area, or a specific part of two dimension space. It has three straight sides and three points. The three angles of a triangle always add up to 180 degrees. It is the polygon with the least possible number of sides.
Types of triangles[change | change source]
Triangles can be grouped according to how long their sides are
- In an equilateral triangle all three sides have the same length
- In an isosceles triangle two sides have the same length
- In a scalene triangle all sides have different lengths
Triangles can also be grouped by their angles.
- A right triangle has one angle that is 90 degrees (a right angle). The side opposite the right angle is the hypotenuse.
- An obtuse triangle has one angle that is larger than 90 degrees (an obtuse angle)
- An acute triangle has angles that are all less than 90 degrees (acute angles)
Uses[change | change source]
Triangles are extremely useful, because the ratio of the length of sides to an angle is always the same. Measuring objects using triangles is called Trigonometry. Some people have spent their entire lives studying triangles for use in trigonometry.
Modern computers usually use triangles to make more complex graphic images or shapes.