## Sunday, October 25, 2015

### Coordinate Geometry - Distance Formula, Section Formula, Centroid and Incenter Coordinates, Slopes Basic Info, Area of Triangle through coordinates with examples

Dear friends from this video I have started taking up the final part of the whole geometry better known as coordinate geometry. Coordinate Geometry is nothing but studying geometrical figures in real world through practical calculations. The very first thing that I have explained in this video is the distance formula which tells us how to calculate the distance between two coordinates in an x-y plane. While telling the distance formula I have also proved it.

After that I have explained the Section Formula which tells us how to calculate the coordinates of a point which divides a line in a particular ratio. There are two different section formulas one for internal division and one for external division. Then I have told how to calculate the coordinates of the centroid and incenter by using the coordinates of the vertices of the triangles. After that the method of finding out the area of a triangle by using the coordinates of the vertices of the triangle has also been explained in the video. After that I have explained some basic things regarding the slope of a line.

While explaining all of the above concepts I have used some questions and solved them to give you a particular understanding of how to approach the questions while giving the real exam. The questions explained by me are listed below -

Ques 1. Find the distance between the points (3,4) and (8,-6)

Ques 2. Find the points which divides the line formed by joining the points (5,2) and (1,-3) in the ratio 1:2 both internally and externally.

Ques 3. Find the midpoint of the line segment made by joining the points (3,2) and (6,4)

Ques 4. Find the area of triangle whose vertices are (1,3), (-7,6) and (5,-1)

Ques 5. What will be the centroid of a triangle whose vertices are (2,4), (6,4) and (2,0)