Coordinate Geometry Class 8 Definition Grid A pattern

Coordinate Geometry Class 8

Definition � Grid – A pattern of horizontal and vertical lines, usually forming squares.

What are the coordinates for the house? A B C D E 4, B When we are listing coordinates; we always state the horizontal coordinate first. 1 2 3 4 5

What are the coordinates for the house? 5 4 3 2 1 (4, 5) State the horizontal coordinate first, followed by the vertical coordinate 1 2 3 4 5

What are the coordinates for the house? 5 4 3 2 1 (0, 0) This point is also known as the origin 1 2 3 4 5

Definition � x axis – a horizontal number line on a coordinate grid. 0 1 2 3 4 5 6 x

Hint �x likes to lie down horizontally. 0 1 2 3 4 5 6 x

Definition � y axis – a vertical number line on a coordinate grid. y 6 5 4 3 2 1 0

Hint � y likes to stand upright or vertically. y 6 5 4 3 2 1 0

Definition � Coordinates – an ordered pair of numbers that give the location of a point on a grid. (3, 4) 6 5 (3, 4) 4 3 2 1 00 1 2 3 4 5 6

Hint The first number is always the x. � The second number is always the y. � 6 5 (3, 4) 4 3 2 1 00 1 2 3 4 5 6

How to plot coordinates � Step 1 – Always find the x value first, by moving horizontally y (2, 3) 6 5 4 3 2 1 00 1 2 3 4 5 6 x

How to plot coordinates � Step 2 – Starting from your new position find the y value by moving vertically y (2, 3) 6 5 4 (2, 3) 3 2 1 00 1 2 3 4 5 6 x

How to find set of coordinates � Step 1 – Find how far over horizontally the point is by counting along the x axis y (5, ) 6 5 4 3 2 1 00 1 2 3 4 5 6 x

How to find coordinates � Step 2 – Now count how far vertically the point is by counting along the y axis y (5, 4) 6 5 4 3 2 1 00 1 2 3 4 5 6 x

What is the coordinate? y (3, 5) 6 5 4 3 2 1 00 1 2 3 4 5 6 x

What is the coordinate? y (2, 6) 6 5 4 3 2 1 00 1 2 3 4 5 6 x

What is the coordinate? y (4, 0) 6 5 4 3 2 1 00 1 2 3 4 5 6 x

What is the coordinate? y (0, 5) 6 5 4 3 2 1 00 1 2 3 4 5 6 x

What is the coordinate? y (1, 1) 6 5 4 3 2 1 00 1 2 3 4 5 6 x

Four quadrants of coordinate grid � When number lines are extended into the negative number lines you add 3 more quadrants to the coordinate grid. y 3 2 1 x 0 -1 -2 -3 -3 -2 -1 0 1 2 3

Four quadrants of coordinate grid � If the x is negative you move to the left of the 0. x = -2 y 3 2 1 x 0 -1 -2 -3 -3 -2 -1 0 1 2 3

Four quadrants of coordinate grid � If the y is negative you move down below the zero. y 3 2 y 1 0 x -1 -2 -3 -3 -2 -1 0 1 2 3 = -3

How to plot in all quadrants � Step 1 - Plot the x number first moving to the left when the number is negative. y 3 2 (-3, -2) 1 x 0 -1 -2 -3 -3 -2 -1 0 1 2 3

How to plot in all quadrants � Step 2 - Plot the y number moving from your new position down 2 when the number is negative. y 3 2 (-3, -2) 1 x 0 -1 -2 -3 -3 -2 -1 0 1 2 3

How to plot in all quadrants � When x is positive and y is negative, plot the coordinate in this manner. y 3 2 (2, -2) 1 0 x -1 -2 -3 -3 -2 -1 0 1 2 3

How to plot all quadrants � When x is negative and y is positive, plot the coordinate in this manner. y 3 2 (-2, 2) 1 x 0 -1 -2 -3 -3 -2 -1 0 1 2 3

Plot this coordinate (-3, -3) y 3 2 1 x 0 -1 -2 -3 -3 -2 -1 0 1 2 3

Plot this coordinate (-1, 2) y 3 2 1 x 0 -1 -2 -3 -3 -2 -1 0 1 2 3

Plot this coordinate (1, -1) y 3 2 1 x 0 -1 -2 -3 -3 -2 -1 0 1 2 3

Plot this coordinate (2, -2) y 3 2 1 x 0 -1 -2 -3 -3 -2 -1 0 1 2 3

Plot this coordinate (-3, -2) y 3 2 1 0 x -1 -2 -3 -3 -2 -1 0 1 2 3

Ex 12 A