1. Graphs The Plot Area Carmelo Ellul
We use graph paper for plotting line graphs and curves. y
The x-axis and the y-axis divide the plot area into QUADRANTS.
The x-axis and the y-axis
The x-axis
2nd
Quadrant
1st
Quadrant
A powerpoint presentation by
Carmelo Ellul
Head of Department (Mathematics)
The x-axis and the y-axis intersect at the O, the ORIGIN. x O
3rd
Quadrant
4th
Quadrant

2. Graphs The Plot Area The x-axis is numbered at equal intervals y
The y-axis is similarly divided into equal intervals 4 3
Each interval On each axis is called a UNIT. 2
1 cm represents each UNIT on the x-axis. 1
2 cm represent each UNIT on the y-axis. -5 -4 -3 -2 -1 1 2 3 -1 -2

3. Graphs
The Plot Area
The x-RANGE is the limits within which the x-axis lies. x y O 1 2 3 -1 -2 -3 -4 -5 4
This is written as:
x-range is from -5 to 3 or
x lies between -5 and 3 or
-5  x  3
y-range
Similarly the y-range
Similarly the y-range can be written as.
y-range is from -2 to 4 or
y lies between -2 and 4 or
-2  y  4
x-range

4. Graphs
The Plot Area
The position of a POINT on the plot area is described by two numbers known as the:
x-coordinate
y-coordinate x y O 1 2 3 -1 -2 -3 -4 -5 4 A
3 on the y-coordinate
A(-2, 3) is the point in line with
-2 on the x-coordinate
Mark the point with a 
(other valid markings are + or )
Label the point A

5. Graphs
RESTART
The Plot Area
END SHOW
The position of a POINT on the plot area is described by two numbers known as the:
x-coordinate
y-coordinate x y O 1 2 3 -1 -2 -3 -4 -5 4 A
-2 on the x-coordinate
A(-2, 3) is the point in line with
3 on the y-coordinate
Mark the point with a 
(other valid markings are + or )
Label the point A