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Basic Geometry and Polygons - Coggle Diagram
Basic Geometry and Polygons
Basic Geometry
types of angles
Right angle (90 degrees)
obtuse (more than (90 less than 360)
acute (less than 90)
straight angle ( 180 degrees)
reflex ( more than 180 less than 360)
Complementary and supplementary angles
comp : 2 angles that add up to 90
supp: 2 angles that add up to 180
reasons in Geometry
Intersecting lines
sum of adjacent (adj) angles on a straight (str) line is 180 ( adj angles on a str. line)
sum of angles at a point is 360 (angles at a point)
vertically opposite angles are equal (vert. opp. angles)
two parallel lines and a transversal
alternate angles are equal. e.g. angle c = angle d (alt angle, PQ//RS
corresponding are equal eg.angle a= angle b (corr. angle PQ//RS)
Quadrilateral
has 4 sides
special qudarilaterals
Parallelogram
diagonals bisect each other
Rhombus
a special parallelogram & kite
diagonals bisect at 90 and bisect int angles
Square
2 sieds of parallel sides, all sides are equal
all angles are 90,
two diangonals are equal, diagonals bisect at right angles, bisect int angles
Trapezium
at least on pair of parallel sides
REctangle
2 pairs of parallel sides
Opposite lengths are equal
all 4 int angles are 90
two diangonals are equal in length
Diagonals bisect each other
Kite
at least two pairs of equal adjacent sides
diagonals cut but dont bisect
sum of int angles =360
Triangle
classification of triangles
Right angle, acute angle and obtuse angle
equilateral, isosceles, scalene
Properties of triangles
angle sum of interior angles of a triangle is 180
Ext angle of triangle= sum of int opp angle