April 13, 2023

Drawing triangles and other shapes

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2. Drawing regular polygons

April 13, 2023

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Have you ever wondered why we divide a circle into 360º, and not another number, like 100? One reason is that 360 has a great number of factors. This makes it easy to divide a circle into equal parts.

360 2 = 180120907260454036304568910÷ 3This is very useful when you need to draw a regular polygon.To do this, you divide a circle by the number of sides you want your polygon to have.This involves using a pair of compasses, a ruler, a pencil a protractor and a bit of division.

Explanation

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April 13, 2023Example

Count round 72º and make another mark.Rotate the protractor so that 0º is at the mark you just made, count round another 72º and make a new mark.Continue to do this until you have made five marks.Join your five marks at the point at which they cross the circle. The finished pentagon.

To draw a regular pentagon.

360º ÷ 5 = 72Divide 360º by 5.

Now draw a circle, with a known radius.Use a protractor, centred on the centre of the circle, to mark a point crossing the circle at 0º.

5 cm

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