This **JEE maths video lecture** is based on a very interesting chapter – **Properties and solution of a triangle.** In this chapter, you will learn a lot of concepts. Also, you get lot of important questions from this chapter in JEE examination.

While watching the video lecture, understand the concepts thoroughly and then make the notes. Do not try to write down everything. During watching the video concentrate more on the concepts. Though this chapter is very interesting, we have observed that students want to stay away from this chapter. Students do not get much confidence in this regard. However, let us tell you that after watching this video lecture you will face no such difficulty.

After watching this video, you will understand all the techniques and will be able to solve all the problems of this chapter.

Firstly, we will understand what notations to be used in a triangle are. Suppose you consider any kind of triangle, which is not a right-angle triangle. Here we will have internal angles, sides, length of sides of angles of a triangle. All these things you will be able to see practically while watching the video lectures. Students will be made to understand the various angles of a triangle with suitable notations where required.

**Properties of triangle** means when you draw a triangle and mark the various angles as A, B, C or a, b, c, then the relation between these alphabets or notations are studied under properties of triangle.

Under solution of triangle, we study that in case out of the six notations, you are given the value of any three numbers such a side or an angle. Here, students should note that while solving this, we need at least one of the lengths of the sides. In case we have all the angles of a triangle, we will not be able to find the solution to the problem. So if out of the 6 values, we know the value of other three (which includes the value of one of the length of a side). Hence, we will use this when we understand solution of a triangle.

Before this we need to understand a very important concept of the **properties of a triangle** which is A+B+C = 180 degrees. The sum of all the interior angles of a triangle is 180 degrees. And this is the important concept to be remembered throughout the chapter.