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Meadowlands 24/11/00
EXPLORING SHAPE
The study of space and shape is called GEOMETRY and dates back many thousands
of years.
The word POLYGON comes from the Greek word meaning many angles.
HEXAGON – meaning having 6 angles
QUADRILATERAL – meaning having 4 angles.
A polygon with 3 sides will be called a triangle. There are several different types of
triangle – SCALENE
ISOSCELES
EQUILATERAL AND RIGHT
ANGLED.
SCALENE – all sides and angles different
ISOSCELES - 2 sides and angles same.
RIGHT ANGLED - having a right angle in it 90º
EQUILATERAL – all sides and angles equal.
A 4 sided polygon could be a SQUARE
RECTANGLE
RHOMBUS
PARALLELOGRAM
TRAPEZIUM
KITE
A 5 sided polygon is called a pentagon
6 sided a hexagon and 8 sided an octogan.
These can be convex – all corners pointing outwards
Concave – at least one corner pointing inwards.
Regular – all sides and angles equal.
WORKSHEET 1 – NAMING THE SHAPES.
Moving on to triangles and looking at calculating the area of them.
All angles add up to 180.
WORKSHEET 2 – FINDING AREA BY COUNTING SQUARES.
Areas of triangles – there is a formula but first we’ll look at how we get to it.
Take a rectangle and cut it in half – 2 triangles. These triangles should be equal.
Divide any shape rectangle into triangles and they should be equal.
Try cutting some out to test this theory! – PRACTICAL WORK
The area of a rectangle is easy to find. LENGTH X BREADTH
WORKSHEET 3 – FINDING AREA BY DRAWING RECTANGLES.
Examples on whiteboard. Can you see from this how to get the formula for the area of
a triangle. BASE X HEIGHT
2
OR THE AREA OF A TRIANGLE IS NORMALLY HALF THAT OF THE
SURROUNDING RECTANGLE.
This is true for ALL triangles. Go back to worksheet 2 and check your answers using
the formula.
WORKSHEET 4 – FINDING THE AREA USING FORMULA.
STUDENTS TO DRAW TRIANGLES TO SCALE USING RULERS AND GIVE
THEM TO EACH OTHER TO WORK OUT THE AREAS OF THEM. MAKE
THEIR OWN WORKSHEETS IN OTHER WORDS! TAKE PLAIN PAPER FOR
THIS!!!