Introduction to Triangles 

We at ask-math believe that educational material should be free for everyone. Please use the content of this website for in-depth understanding of the concepts. Additionally, we have created and posted videos on our youtube.

We also offer One to One / Group Tutoring sessions / Homework help for Mathematics from Grade 4th to 12th for algebra, geometry, trigonometry, pre-calculus, and calculus for US, UK, Europe, South east Asia and UAE students.

Affiliations with Schools & Educational institutions are also welcome.

Please reach out to us on [email protected] / Whatsapp +919998367796 / Skype id: anitagovilkar.abhijit

We will be happy to post videos as per your requirements also. Do write to us.

In this section we will discuss about introduction to triangles.

A plane figure formed three non-parallel line segments is called a triangle.

Non-collinear points join to form a Triangle.

Parts of Triangles :

Vertices : A, B, C

Sides : AB, BC , CA

Angles : ∠BAC, ∠ABC, ∠ACB.

Opposite Sides : side opposite to
∠BAC ----> BC
∠ABC ----> AC
∠ACB ----> AB

Interior and Exterior Of Triangle

In triangle ABC, there are three parts :

Interior region : The points lie inside the region enclosed by triangle.
On the sides : The points lie on the sides of the triangle.
Exterior region : The points lie outside the region enclosed by triangle.

Example


Interior points : P and S

Exterior points : Q

On the sides : R and T

Triangular region

The interior of Δ ABC together with the ΔABC itself, is called the triangular region ABC.

Practice

In the given triangle ABC answer the following questions:

(i) Side opposite to angle Q.

(ii) Vertex opposite to Side QR.

(iii) Angle opposite to side PR.

(iv) All six elements of triangle PQR.

(v) Name the points which are in the interior region of ΔPQR.

(vi) Name the points which are in the exterior region of ΔPQR.

(vii) Name the points which are on the ΔPQR.

Answers
(i) Side opposite to angle Q.

(ii) Vertex opposite to Side QR.

(iii) Angle opposite to side PR.

(iv) All six elements of triangle PQR.

(v) Name the points which are in the interior region of ΔPQR.

(vi) Name the points which are in the exterior region of ΔPQR.

(vii) Name the points which are on the ΔPQR.

Answers

---

Triangles

• Introduction to Triangles
• Types of Triangles on the basis of Sides
• Types of Triangles on the basis of Angles
• Angle Sum Property of Triangles
• Exterior and Interior angles of Triangle
• Triangle Inequality Property
• Congruent Triangles
• Postulates of Congruent Triangle
• Inequality in Triangle

Geometry

7th grade math

Home Page

Russia-Ukraine crisis update - 3rd Mar 2022

The UN General assembly voted at an emergency session to demand an immediate halt to Moscow's attack on Ukraine and withdrawal of Russian troops.