Similar figures have the same
shape but can be different sizes
It can either be an enlargement or
reduction
Two polygons are similar
if:
Their corresponding
angles are equal
(matching angles)
Their corresponding
sides are in the same
proportion
The symbol for similar is
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If two triangles have equal
corresponding angles, their
corresponding sides are in proportion
If two triangles have corresponding sides in
proportion, corresponding angles are equal
You have to put the triangle in the order
that it corresponds with the other triangle
to find out whether it is similar
Congruency
To prove congruency
compare, sides and
anlges.
Congruent means identical
and equal in all respects (2
triangles must be compared)
There are 4 cases of
congruency
1. If three sides of a triangle are respectively
equal to the three sides of the other triangle
then the two triangles are congruent (SSS)
2. If two sides and included angle of a triangle is
respectively equal to the two sides and the included
angle of another triangle ten they are congruent (SAS)
3.If two angles and one side of one
triangle are respectively equal to two
angles and the corresponding side of
another triangle, they are congruent
(AAS or ASA)
4.If the hypotenuse and one side of a right-angled triangle are
respectively equal to the hypotenuse and one side of another
right-angled triangle, they are congruent (RHS)