4785 /www/nrich/html/content/id/4785/ 1 2011-02-01T00:00:01 <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><br></br> Have you ever tried drawing the same picture but a different size? <br></br> Here is a very simple picture of a cat's face, drawn on a square grid:<br></br> <br></br> <mdo:image width="345" height="345" alt="Cat on a grid" src="catOnGrid.jpg"></mdo:image><br></br> <br></br> The grid lines on this picture will help to make it easier to draw different sizes.<br></br> Using grid lines to help you, can you draw the same cat's face but twice as wide and twice as high?<br></br> Can you draw the cat's face half as wide and half as long? <br></br> You may like to use <a href="/content/id/4785/cat%20grids.doc">this sheet </a><a href="/content/id/4785/cat%20grids.doc"></a> with the grids drawn for you.<br></br> <br></br> We would love to receive your pictures, so please do scan them in and send them to us.<br></br></mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><br></br> <p class="editorial">Tunc from FMV Erenkoy Primary School sent us these images:</p> <br></br> <div style="text-align: center;"><mdo:image alt="first drawing" height="380" src="sol1.gif" width="400"></mdo:image></div> <br></br> <div style="text-align: center;"><mdo:image alt="second drawing" height="186" src="sol2.gif" width="200"></mdo:image></div> <div style="text-align: center;"> </div> <div> <p><span class="editorial">We had a separate email from Ephi Light</span></p> <p><br></br> I am a 4th grade student from the Jewish Day School of Metropolitan Seattle. Today at school I recieved this worksheet from my teacher. I worked on this for all my 45 min. in class. I have worked hard and think this is a great piece of art.</p> <p style="text-align: center;"><mdo:image src="the%20cat.jpg"></mdo:image></p> <p> </p> </div> <p class="editorial">Well done - you&#39;ve used the grid lines very carefully.</p> <p><br></br> <br></br>  </p></mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><br></br> <h3><span style="font-weight: bold;">Why do this problem?</span></h3> <a href="http://nrich.maths.org/4785&amp;part=">This problem</a> begins to introduce children to the idea of scale.<br></br> <h3>Key questions</h3> <div>How many squares along the top edge of the grid is the point of each ear?</div> <div>So can you work out where the point will go on a different grid?</div> <div>How many squares along and down does each eye go?</div> <br></br> <h3>Possible extension</h3> The questions have deliberately stuck to grids that are in the same proportion as the original grid, but you could ask children how the cat's face would change if, for example, the width stayed the same but the length was halved. This could produce an interesting discussion about why this new cat looks different to ones drawn in a proportionate grid.<br></br> <h3>Possible support</h3> You may like to use <a href="/content/id/4785/cat%20grids.doc">this sheet</a> with the grids drawn for you.<br></br> <br></br></mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><br></br> You could start by drawing the outline of the cat's face. How many squares along the top edge of the grid is the point of each ear? So can you work out where the point will go on a different grid? <br></br>How many squares along and down does each eye go?<br></br></mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0">This problem begins to introduce children to the idea of scale. The questions have deliberately stuck to grids that are in the same proportion as the original grid, but you could ask children how the cat's face would change if, for example, the width stayed the same but the length was halved. This could produce an interesting discussion about why this new cat looks different to ones drawn in a proportionate grid. <br></br></mdoxml> 5 3 1 0 0 0 0 Use the grids to draw pictures to different scales. Transformations and their Properties Enlargements Fractions, Decimals, Percentages, Ratio and Proportion Direct & inverse proportion