Download 4.2 quadrilaterals

GEOMETRY:2-D SHAPES
Two-dimensional (2-D) shapes have area and perimeters. All points on 2-D shapes are
in the same plane. Below are the 2-D shapes you need to recognise along with some of
their important properties.
4.1 TRIANGLES
Triangles have 3 sides. There are several types of triangle:
Right-angled:
has a 90º angle
Equilateral:
three sides equal and three angles equal
Isosceles:
two sides equal and base angles equal
Scalene:
all the sides and angles are different
4.2 QUADRILATERALS
Quadrilaterals have four sides. There are several types of quadrilateral.
Square:
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Four lines of symmetry
All angles are 90º
All sides equal
Two pairs of parallel sides
Rectangle:
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Four lines of symmetry
All angles are 90º
Opposite sides equal
Two pairs of parallel sides
Parallelogram:
 No lines of symmetry
 Opposite sides are equal and parallel
 Opposites angles are equal
Rhombus:
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Two lines of symmetry
All sides are equal
Opposites side are parallel
Opposites angles are equal
Kite:
 One line of symmetry
 Two pairs of adjacent sides are equal
Trapezium:
 No lines of symmetry
 One pair of parallel sides
4.3 POLYGONS
Polygons are 2-D shapes with straight sides. Regular polygons are shapes with all sides
and angles equal.
Regular Pentagon:
 Five equal sides
 Rotational symmetry of order 5
 Five lines of symmetry
Regular Hexagon:
 Six equal sides
 Rotational symmetry of order 6
 Six lines of symmetry
Regular Octagon:
 Eight equal sides
 Rotational symmetry of order 8
 Eight lines of symmetry
4.4 THE CIRCLE AND THE CIRCUMFERENCE
The circumference is the distance around the outside edge of the circle.
The diameter is twice the radius.
A arc is part of the circumference.
A chord is a line that joins two points on the circumference, the chord doesn´t go
through the centre.
A tangent touches the circle at one point only
4.5 PERIMETERS
Perimeters is the distance all the way around the outside of a 2-D shape. Units of
perimeter are mm, cm and m.
4.6 AREAS
The area of a 2-D shape is the amount of space it covers. Units of area
mm 2 , cm 2 , and m 2
Area of a rectangle:
Area = length x width
A=lxw
Area of a parallelogram:
Area = base x perpendicular height
A=bxh
Area of a triangle:
Area = ½ x base x perpendicular height
A=½xbxh
Area of a trapezium:
Area = ½ x (sum of parallel sides) x
(perpendicular height between sides)
Area = ½ x (a+b) x h
Area of a circle:
Area = π x (radius)²
Area
are