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Name the shape that matches this description.
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It has five sides.
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It has five angles.
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It is closed.
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In this question, we’re being asked to identify the name of a shape based on some information that we’ve been given.
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What clues do we know?
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Let’s start by highlighting the important information in the problem.
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We’re told that the shape has five sides.
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It has five angles.
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And we’re also told that it’s a closed shape.
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Let’s think about what each of those clues mean.
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Now the sides of a shape are the lines that are used to make it.
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So we know that this shape is formed from five lines.
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Here’s an example of a shape with five sides: one, two, three, four, five.
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When we talk about the angles of a shape, we usually mean the angles inside the shape, unless we say otherwise.
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These are the angles between each side, and they’re found in each of the vertices or corners of the shape.
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So let’s count the angles in the vertices of this five-sided shape that we’ve drawn: one, two, three, four, five.
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So our shape has five sides and five angles.
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And our final clue is that the shape is closed.
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This means that there are no gaps in between any of the sides of the shape.
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If we take our pencil around the sides of the shape, we’ll arrive back where we started without having to jump across any gaps.
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So we can see that that’s true and that there are no gaps.
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It’s a closed shape.
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So this shape has five sides, five angles, and is closed.
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But what is its name?
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Now knowing where different words come from is important in maths.
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It can really help us understand what mathematical words mean.
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For example, another word for a 2D shape is a polygon, which is made up of two word roots.
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“Poly” means many, and “gon” means angles or angled, a many-angled shape, a polygon.
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But do you know the word root that means “five” so that we can use it for a five-angled shape?
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Well, the word root “penta” means five.
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And so the name of a shape that has five sides, five angles, and is closed is a pentagon.