Plot & locate points on the coordinate plane (four quadrants)
Theory
The number plane has a horizontal \(x\)-axis and a vertical \(y\)-axis that cross at the origin \((0, 0)\). A point is given by an ordered pair \((x, y)\): go across first (left for negative), then up or down (down for negative). The axes split the plane into four quadrants. This Year 6 maths page shows how to read and plot points anywhere on the plane, name the quadrant, and use coordinates to find distances and complete shapes.
The \(x\)-axis is horizontal and the \(y\)-axis is vertical. They meet at the origin, \((0, 0)\).
An ordered pair \((x, y)\) gives the \(x\)-coordinate first (across: right is positive, left is negative), then the \(y\)-coordinate (up is positive, down is negative).
The quadrants are numbered anticlockwise from the top right: first \((+, +)\), second \((-, +)\), third \((-, -)\), fourth \((+, -)\).
A point on the \(x\)-axis has \(y = 0\), like \((3, 0)\). A point on the \(y\)-axis has \(x = 0\), like \((0, -2)\). Points on the axes are not in any quadrant.
Along a grid line, the distance between two points is the difference of the coordinates that change: from \((-3, 2)\) to \((4, 2)\) is \(4 - (-3) = 7\) units.
Signs of the coordinates in each quadrant:
| Quadrant | x | y | Example |
|---|---|---|---|
| First | \(+\) | \(+\) | \((2, 3)\) |
| Second | \(-\) | \(+\) | \((-2, 5)\) |
| Third | \(-\) | \(-\) | \((-5, -1)\) |
| Fourth | \(+\) | \(-\) | \((4, -3)\) |
Plotting a point (x, y)
- Start at the origin.
- Move across \(x\) units: right if positive, left if negative.
- Move up or down \(y\) units: up if positive, down if negative. Mark the point.
Reading a point
- Read straight down or up to the \(x\)-axis for \(x\), then across to the \(y\)-axis for \(y\).
- Write \((x, y)\) with the signs.
A \((4, -3)\), B \((-2, 5)\), C \((-5, -1)\).
(i) \((-1, 4)\)
(ii) \((3, -5)\)
(iii) \((-2, -2)\)
(i) Second
(ii) Fourth
(iii) Third
\((0, -2)\) is on the \(y\)-axis, \(2\) below the origin. \((3, 0)\) is on the \(x\)-axis, \(3\) to the right. Neither is in a quadrant.
The second quadrant \((-, +)\): left of the \(y\)-axis and above the \(x\)-axis.
| \(4 - (-3)\) | \(=\) | \(7\) |
| \(2 - (-3)\) | \(=\) | \(5\) |
PQ is \(7\) units and QR is \(5\) units.
It is below \((-3, 2)\) and level with \((4, -3)\): \((-3, -3)\).
| \(1 - 4\) | \(=\) | \(-3\) |
| \(-2 + 3\) | \(=\) | \(1\) |
\((-3, 1)\), in the second quadrant.
She plotted \((5, -2)\). For \((-2, 5)\), go \(2\) left first, then \(5\) up (point B in the first diagram).
Common pitfalls
Frequently asked questions
What is the origin?
The point \((0, 0)\) where the axes cross.
Which number comes first in a coordinate pair?
The \(x\)-coordinate (across).
Which quadrant has both coordinates negative?
The third quadrant.
Where is the point (0, β2)?
On the \(y\)-axis, \(2\) units below the origin.
How far is it from (β3, 2) to (4, 2)?
\(7\) units.