A triangle is created of three line segments. The line segments intersect in your endpoints. To name a triangle we frequently use that vertices (the surname of the endpoints). The triangle listed below is named ABC.

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A triangle has three angles. The amount of the actions of the angles is constantly 180° in a triangle.

We have actually different types of triangles. A triangle is classified by the angles and by the variety of congruent sides.

A triangle that has three acute angels is referred to as an acute triangle.


A triangle that has actually one best angle is dubbed a appropriate triangle.


A triangle that has actually one obtuse edge is referred to as an obtuse triangle.


When a triangle has three congruent sides, we call the triangle an it is provided triangle. We note the congruent political parties by a slash mark. The angles in an it is intended triangle are constantly 60°.


When a triangle has actually two congruent political parties it is called an isosceles triangle. The angle opposite to the 2 sides of the same size are congruent.


A triangle without any congruent sides or angles is dubbed a scalene triangle.

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When two triangles space congruent it method that they have the exact same size and shape. This method that they have the same angles. The red cut marks display us i m sorry sides and also angles that space congruent Congruency is displayed by this symbol



$$\beginmatrix A\cong X & & AB\cong XY\\ B\cong Y & & BC\cong YZ\\ C\cong Z & & AC\cong XZ \endmatrix$$

Triangles that have congruent angles yet not the same size are dubbed similar. Comparable triangles have sides that are proportional. Similarity is displayed by this symbol



$$\bigtriangleup ABC\sim \bigtriangleup XYZ$$

$$A=X,\: \: B=Y,\: \: C=Z$$



Find x in the similar triangles.


We recognize that due to the fact that the triangle are comparable the sides room proportional which method that


$$x=\frac14\cdot 321=\frac4221=2$$


Video lesson

Find out whether the triangles are right, isosceles, acute, scalene, obtuse or equilateral