What is Triangle? Triangle is one of the fundamental figures for Euclidean geometry. It is a three-sided polygon. There few elements required to create a triangle. The elements are
- 3 sides
- The sum of all interior angles from the three sides exactly equals to 180 degrees.
The image below shows a right triangle with their associated angle values. Note 90 + 45 + 45 = 180 degrees.
All triangles are generally classified in two different ways, by their relative lengths of sides or by their internal angles.
Classification of triangle by sides:
Triangles by their relative sides are classified into three different types; Equilateral, Isosceles and Scalene.
Equilateral triangles are triangles that have all the congruent or equal sides. Since all sides are equal, they create equal angles each measuring 60°. Below is an image of equilateral triangle which shows all sides and all angles are equal to each other.
Isosceles triangles are type of triangles that have two congruent or equal legs and two angles that are equal. It is easy to figure out the 3rd angle of an isosceles triangle based on one angle. Below is an image of isosceles triangle shows two congruent sides and two congruent angles.
Scalene triangles are type of triangles that have no congruent sides thus no congruent angles. Each side is different from other and each angle is different. Below is an image of a Scalene Triangle.
Classification of triangle by angles:
Triangles by their relative angles are classified into three different types; Right, Obtuse, and acute.
What is right triangle? Right triangle is a type of triangle which has one angle measuring to 90° or a right angle. Unlike other triangles, right triangle has many parts with specific names. The image below shows different parts of the triangle. Pythagorean Theorem calculator within this site to calculate different parts of right triangle.
Obtuse triangle is a type of triangle that has one angle measuring more than 90°. This type of triangle generally tends to have a slanted look. Notice that only one angle of an obtuse triangle is greater than 90° or else it will not be a triangle. Below is an image of obtuse triangle.
Acute triangle is a type of triangle where all angles equals to 180 degrees but they all are smaller than 90 degrees individually. Below is a picture of acute triangle.
Calculation of Triangle:
There are three important triangle calculations that can be done across all types of triangle. They are Area, base and Height. The image below shows the base and height.
An area of a triangle is calculated by multiplying base with its height and dividing it by 2.
The Triangle Calculator above allows calculating all parts of a triangle.
Pythagorean Theorem calculator - Calculate different aspects of Pythagorean Theorem
Rectangle Calculator – Calculate different aspects of rectangle
Square Calculator – Calculate different aspects of Square
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