# 198. You sunk my rectangle!

How about a game of ‘Battleships’ with a graphicalÂ twist? My Year 7 class loved playing this game and we developed understanding without resorting to tediously drawing out lots of graphs.

Objective

To be able to draw and label lines parallel to the x or y axes ie x=1, y=3

Equipment

• Squared paper
• Pencil
• Coloured pens or pencils
• Ruler or straight edge

Preparation

1. In pairs, agree the size of a set of axes and draw two identical sets each. Negative axes can be used as an extension.

2. On one set of axes draw a rectangle, making sure the edges are on whole numbers.

3. Extend the edges of the rectangle to give you two horizontal and two vertical lines. Label the lines accordingly. You are now ready to play!

Playing the game

1. Players take it in turns to guess a straight line eg x=3. Their partnerÂ says ‘Hit’ if it is the edge of their rectangle and ‘Miss’ if it isn’t. This information is recorded on the players second grid so they can keep track of their guesses.

2. The game continues until a rectangle is revealed:

3. The player must then label where the lines intersect. The losing player may find it useful to continue guessing.

Extension: What do thy notice about the co-ordinates and the equations of their lines?

4. What is the area of the rectangle?

Extension: Is there a link between the co-ordinates and the area?