2d shapes vocabulary let’s see how many words we use to describe or are connected with 2d shapes
TRANSCRIPT
Symmetry is when both sides of the shape or pattern are the same when viewed from
the central line. Some shapes have a line (or lines) of symmetry -
sometimes called 'mirror lines'.
In each case, if you stood a mirror on the line of symmetry, the shape would look unchanged. (You can check this by using a mirror, or by tracing a shape and folding it along the mirror line.)
<<< <<<
<<< <<<
Patterns can also be symmetrical
**** +++ ****
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**** +++ ****
Draw the line(s) of symmetry on the shapes above
Regular polygons are a never-ending series of shapes with one special feature
All the sides and angles are the same size.
Do you know any regular polygons?.
Here are some a regular polygons?
Equilateral Triangle
3 sides
3 equal angles
4 sides
4 equal angles
6 sides
6 equal angles
8 sides
8 equal angles
Square
Hexagon Octagon
Click anywhere on the page until you fill all the boxes
What are the properties of these regular polygons?
Pentagon
Heptagon
Decagon
Nonagon
Write your answers and check them by clicking 4 times
A pentagon has 5 equal sides and 5 equal angles
A heptagon has 7 equal sides and 7 equal angles
A decagon has 10 equal sides and 10 equal angles
A nonagon has 9 equal sides and 9 equal angles
• A circle is a flat round shape.
• The distance from the centre to the outside of the circle is always equal.
Circle Vocabulary
A circle has one side around the
outside called the circumference
Diameter is any line across the circle that passes through the centre of the circle
Radius is any line that is drawn between the centre of the circle to the circumference
Parallel Lines
Two lines are parallel if they are always the same distance apart. This means they will never meet even if they are extended
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<
<The arrowhead indicate that these two lines are
parallel
Parallel Lines
Some shapes have 1 or 2 pairs of parallel lines
<The arrowhead indicate that these two lines are
Sometimes << arrowheads are used to show a second pair of
parallel lines
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<
<
<<
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<<
<<
<<<<
2D ( 2 dimensional)Here is a line. This has one dimension (length)
All flat shapes have two dimensions,
length and width (breadth). So they are called 2D.
What is an angle?When two lines join two angles are formed.
When two lines intersect 4 angles are formed
XX
X
X
X
X
Angles are measured with a protractor
6001200
Two angles are formed. One angle is 1200 and the other is 600.
Together they make 1800.
What is a complex shape?A complex shape is a shape that can be broken into smaller shapes. What shapes can you see in these complex shapes?
Recap
3. Name 6 regular polygons. List their properties
1. What is a polygon?
2. What is a regular polygon?
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Recap Answers1. A polygon is a many sided shape
2. A regular polygon is a shape with equal sides and equal angles
3 Any of the following:• Equilateral Triangle – 3 equal sides & angles Square – 4 equal sides 4 right-angles Pentagon – 5 equal sides & angles Hexagon – 6 equal sides & angles Heptagon – 7 equal sides & angles Octagon – 8 equal sides & angles Nonagon – 9 equal sides & angles Decagon – 10 equal sides & angles