Transcript Shape1-2Dx

MATHEMATICS
2D Shapes
Aims of the Lesson
• To learn most of the keywords associated with
shapes and angles.
• To recognise the 4 main basic 2D shapes.
• To recognise the 3 types of triangle and learn to
given them their full mathematical name.
• To recognise and name the 6 main types of
quadrilateral.
Keywords
• Save and printout ShapeKW.docx
• Separate the table at the top from the descriptors
at the bottom which should be separated by
cutting along the lines.
• As you progress through the next few slides, you
will be able to match the descriptor with its
keyword and stick it into the table.
Keywords – lines
• A line which always travels in the same direction
without bending is straight, but a line deviating
from the straight in a smooth way is curved.
• A line which is lying flat is horizontal, whilst a line
which is standing upright is vertical.
• Lines that meet at right angles are perpendicular.
• Lines that are always the same distance apart and
therefore always travelling in the same direction
together are parallel.
Keywords – 2D shapes
• Any 3-sided flat (2D) shape is called a triangle.
• Any 4-sided flat (2D) shape is called a
quadrilateral.
• All other flat (2D) shapes with ‘many’ sides are
called polygons.
• If a shape’s sides are all the same length AND all
its angles are equal, then it is a regular shape.
Keywords – 3D shapes
• A 3D shape with many triangular faces is called a
polyhedron.
• The corner of a 3D shape is called a vertex
(plural of this is vertices).
• The flat side of a 3D shape is called a face.
• Where two flat sides meet, they form an edge.
Lead-In
• As a lead into the next part of the lesson please
work through the MyMaths lesson called:
• Shape > 2D and 3D Shapes > 2D and 3D Shapes
• It can be found at this URL:
• http://app.mymaths.co.uk/241-resource/2d-and-3d-shapes
Types of Triangle
• A triangle with 3 equal sides and 3 equal angles
is called an equilateral triangle.
• It will also have 3 lines of symmetry and rotational
symmetry of order 3.
Types of Triangle
• A triangle with 2 equal sides and 2 equal angles
is called an isosceles triangle.
• It has 1 line of symmetry which folds one of the
equal sides and angles over on to the other side.
Types of Triangle
• A triangle with no equal sides or equal angles is
called a scalene triangle.
• It has no lines of symmetry or rotational symmetry.
Naming triangles
• At KS3 you only have to name a triangle using
the terms equilateral, isosceles or scalene
(followed by the word triangle).
• At KS4, if it is an isosceles or scalene triangle you
should also find the largest angle and write the
angle type in front of the type of triangle.
Examples
This triangle has two sides
marked as being equal.
KS3: It is an isosceles triangle
The largest
here and is
This
triangleangle
has 3isangles
clearly larger
thanequal.
a right angle
marked
as being
This
has no sides or
so…triangle
KS3:
It is an equilateral triangle
angles marked as equal
KS4: ItIt is
is an
an equilateral
obtuse-angled
KS4:
triangle
(although
it does
have one
right
isosceles triangle
angle marked).
KS3: It is a scalene triangle
The largest angle is the right
angle (as the other two angles
are both acute) so…
KS4: It is a right-angled
scalene triangle
Lead-In
• As a lead into the rest of the lesson please work
through the MyMaths lesson called:
• Shape > 2D and 3D Shapes > Lines and
Quadrilaterals
• It can be found at this URL:
• http://app.mymaths.co.uk/245-resource/lines-andquadrilaterals
Types of Quadrilateral
• This is a RECTANGLE.
• It has 2 pairs of equal sides.
• It has 4 equal angles (all 90°).
• It has 2 pairs of parallel sides.
• It has 2 lines of symmetry and
rotational symmetry of order 2.
Types of Quadrilateral
• This is a SQUARE.
• It has 4 equal sides.
• It has 4 equal angles (all 90°).
• It has 2 pairs of parallel sides.
• It has 4 lines of symmetry and
rotational symmetry of order 4.
• It’s diagonal lines cross at 90°.
Types of Quadrilateral
• This is a PARALLELOGRAM
•
•
•
•
(it looks like a tilted rectangle).
It has 2 pairs of equal sides.
It has 2 pairs of equal angles
(opposite angles are equal).
It has 2 pairs of parallel sides.
It has 0 lines of symmetry but
rotational symmetry of order 2.
Types of Quadrilateral
• This is a RHOMBUS (it looks
•
•
•
•
•
like a tilted square).
It has 4 equal sides.
It has 2 pairs of equal angles
(opposite angles are equal).
It has 2 pairs of parallel sides.
It has 2 lines of symmetry and
rotational symmetry of order 2.
It’s diagonal lines cross at 90°.
Types of Quadrilateral
• This is a KITE.
• It has 2 pairs of equal sides.
• It has 1 pair of equal angles.
• It has NO parallel sides.
• It has 1 line of symmetry.
• It’s diagonal lines cross at 90°.
Types of Quadrilateral
• This is a TRAPEZIUM.
• It has 1 pair of parallel sides.
Sometimes you will come
across an ISOSCELES
TRAPEZIUM which also has…
• 1 pair of equal sides
• 2 pairs of equal angles and
• 1 line of symmetry
What next?
• Print out the notes called Shape1-2D.docx. Read through
them and make sure you answer any questions. You can
always review the powerpoint or any of the MyMaths
lessons again to help you.
• Now move on to the Angle1-Types powerpoint