Straight lines - 17 Problem types that can come in IIT JEE - JEE Main 2025

PRACBEE REVISION PROGRAM

We will add the comparison of the syllabus between JEE Main 2023 and JEE main 2024, so you have an exact idea of the differences. Besides that, we are also attaching the Mindmap of the chapter, so you know which topics and subtopics are covered in Straight Lines chapter for IIT JEE - JEE Main and JEE Advanced, and how these are interlinked with each other. That helps you cover the entire Straight Lines chapter comprehensively and also ensure you do not miss any single subtopic or concept from it.

Since the video has 5-6 questions from each of the 17 types of problems in Straight lines, mostly from Past Year Questions of JEE Main, we are keeping 2 questions per type in the blog. We will add the list of the 17 problem types followed by 2 questions from each type.

We are going to systematically start with the weightage of the topic then go into the subtopics that need to be covered then go into more deeper points of what exactly there is in the syllabus using mind maps and ultimately come on to the 17 problem types that can be asked in Straight Lines chapter.

So, without any further delay let us start with the weightage of this topic, which is usually around one question in JEE Main. Statistically speaking there has been one question from straight lines in the last 2 to 3 years now. If I go into the exact syllabus comparation between 2023 and 2024, you can see that there was one major change that is exclusion of equation of internal and external bis sector of an angle between two lines and family of lines.

So these two ideas were removed from the syllabus and largely speaking they stuck with this syllabus change because in 20124 exam there was no question related to angle bisector or family of lines in the exam. If we do a detailed analysis of mind maps the idea of this chapter starts with a point. In point we start with the concept of different kinds of coordinate that are there and in that there are two three important ideas.

Syllabus comparison of Straight lines for IIT JEE between 2023 and 2024

Mindmap of the chapter – Straight Lines

Problem Types discussion

One is nothing but the locus - how to find Locus, what are the four steps of finding the locus, then we move towards transformation of axis. We talk about shifting of origin and then we talk about rotation of axis. Ultimately, we move towards the idea of slope and how to find the angle between two lines and here we also see what will happen if two lines will become parallel and perpendicular.

Then we slowly move towards finding the equation of a straight line so in that we start with slope intercept form, slope Point form, two-point form, normal form, parametric form, distance form and then equation through point and equally inclined to a line.

These kinds of situations we discussed then we move towards perpendicularity. Questions in which we have a point and we have to find perpendicular distance, foot of perpendicular and image such kind of conditions. Then we move into perpendicular distance between two parallel lines. Our discussion further moves into angle bisector to angle bisector containing origin, acute angle bisectors containing a point.

After these three discussions we ultimately move towards family of lines. So now we are dealing with multiple lines in that we do systematic discussion of how to write the equation of a straight line passing through intersection of two lines, then we reverse the idea and we talk about the set of line that is given and how to split it into family of lines and get the point. Then we do geometry-based discretion based on congruency of lines, so now if you have three set of lines then what can happen is basically, they can intersect at a point.

The congruency condition will come if they do not intersect, then they will form triangles and different kinds of centres and this is a very important discussion because now this discussion is also going into solution of triangles. So, we will have concepts of centroid, geometry of centroid. We'll have orthocentre, geometry of orthocentres. Those ideas we need to do in terms of different kinds of centres. Then the idea of reflection.

If you go a little bit deeper, we will have also had a concept of pair of straight lines that you do not need to cover at the level of JEE, means so in this mind map what you can observe is we systematically start with a straight line then we move into idea of a point and straight line then we move may bringing more straight lines so we have two straight lines. And we can talk about their angles, perpendicular lines, parallel lines and then the concept of angle bisector.

Then then we bring in three lines and we talk about that congruency and kinds of triangles and the centres of the triangles that can be formed. Then we move towards family of lines concept and ultimately the pair of straight lines. So, it is a very systematic way of moving across the topic if you move in this manner.

It is very easy to remember the content now the first kind of problem type that we are going to cover is nothing but the area of polygons. This has been very important area and there have been at least more than 10 questions from this topic in previous 5 years

Topic-wise Previous Year Questions

We hope you enjoyed this blog as well as the video, in which we went into the details of different kinds of problems that can be formed from Straight Lines chapter in JEE Main, and how to solve them.

If you like this series, you can also opt for Pracbee’s detailed revision program in which we have divided 10 weeks into 10 blocks and every week we cover one block. In that you have a target of solving one chapter in a day and this lecture series is in combination of that revision program.

Also you can drop a comment on the video or write a review of this article. You can also let us know what more we can do for you to make your final 2 months preparstion very smooth and effective. If you found this useful, it is highly recommendable that you click on the link in the description box and try and join the series as well.

All the best for your JEE Main 2025.