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Maths

Coordinates and Plotting Shapes

Overview

Students extend their coordinate work into negative values across all four quadrants, plotting and identifying shapes, and using coordinates to solve geometric problems.

Learning Objective
Students plot and read coordinates in all four quadrants, use coordinates to describe and draw polygons, and find missing vertices of shapes.

Resources needed

  • Coordinate grids (4-quadrant, from −5 to 5)
  • Ruler
  • Pencil

Lesson stages

0 / 7 done
  1. 1 Display a four-quadrant grid. Ask: 'What is different about quadrants 2, 3 and 4?' (Negative coordinates.) Practise reading: (−3, 2), (4, −1), (−2, −3). 'Along the corridor, up the stairs — x first, then y.'
  2. 2 Students plot eight coordinates, including points in all four quadrants. They label each point with its coordinates. Check accuracy by comparing with a partner.
  3. 3 Give four coordinates: (1,1), (4,1), (4,4), (1,4). Students plot and join the points. What shape is it? (Square.) Repeat with three more sets — students name each polygon.
  4. 4 Three vertices of a rectangle are given: (−2, 3), (3, 3), (3, −1). 'Where is the fourth vertex?' Students reason using the properties of a rectangle (right angles, parallel sides). (−2, −1).
  5. 5 A point is at (3, −2). 'If I reflect it in the x-axis, where does it go?' (3, 2). 'In the y-axis?' (−3, −2). Students predict and verify by plotting. Generalise the rules.
  6. 6 Students choose their own polygon (at least 5 sides) and record all vertices as coordinates. They swap with a partner who recreates it from the coordinates alone. Do both versions match?
  7. 7 Coordinates are used in mapping, GPS, architecture and video game design. Show a simple example. 'Every pixel on a screen has an (x, y) coordinate.'

Tap a step to mark it as done.

Variations

  • Extend to midpoints of line segments
  • Calculate the length of horizontal/vertical segments
  • Introduce the distance formula for diagonal segments
More information

Display: x-axis, y-axis, origin, quadrant, coordinates, plot. Use the mnemonic 'along the corridor, up the stairs' (x before y). Emphasise (x, y) order consistently.

Begin in the first quadrant only (positive coordinates) before extending. Provide pre-printed grids to avoid drawing errors. Label quadrant numbers.

Do students plot x first (horizontal) then y? Do they handle negative coordinates correctly? Do they use shape properties to find missing vertices?

Draw a four-quadrant grid on plain paper with a ruler. No printed resources required.

Students may plot (y, x) instead of (x, y). Reinforce the convention constantly. Also: negative y is below the x-axis, negative x is left of the y-axis.