Intermediate II Geometry, Coordinate Geometry, and Measurement (5-6 new curriculum) Flashcards
reflection symmetry
2D: if there is a straight line over which the shape reflects and the two halves match exactly
3D: if there is a plane over which the shape reflects and the two halves match exactly
In a regular polygon, the number of sides equals the number of reflection symmetries.
The circle has infinitely many reflection symmetries.
rotation symmetry
if it exactly overlaps itself one or more times within a rotation of less than 360 degrees around its centre point
In a regular polygon, the number of sides equals the number of rotation symmetries.
The circle has infinitely many rotation symmetries.
order of rotation (order of rotation symmetry)
the number of times a shape coincides with itself within a rotation of 360 degrees around its centre point
central symmetry
rotational symmetry by 180 degrees
the straight line that connects a point with its image in the central symmetry passes through the centre of rotation
How can a symmetrical shape be mapped?
by any combination of reflections and rotations
tessellation
the tiling of a plane with symmetrical shapes
symmetry
a relationship within a shape that can be mapped exactly onto itself other through reflection or rotation
e.g.:
the two parts of the shape for example can be congruent to each other and thus make the full shape symmetrical
congruent
two things that can be placed on top of one another without changing any lengths (maybe by using a rigid motion and then reflection at the end)
a relationship between two shapes of identical size and shape
congruence is not dependent on orientation or location of the shapes
What are some units of area?
square centimetres (equivalent to the area of a square measuring 1 centimetre by 1 centimetre)
square metres
square kilometres
(many more exist but are not listed here)
exponent 2 on the unit
Among all rectangles with the same area, the square has the (least/most) perimetre
least
Can rectangles with the same area have different perimetres?
yes
parallelogram
any quadrilateral with two pairs of parallel and equal sides
any side of the parallelogram can be interpreted as the base
the height of a parallelogram is the perpendicular distance from its base to its opposite side
triangle area
half the area of the parallelogram with the same base and height
A = hb/2
If two triangles have the same base and height, then what can we say about their areas?
the areas are also the same
parallelogram area
the product of the perpendicular base and height
A = bh