Download Wednesday Similar Triangles

WARM UP
Determine
whether the following
are a stretch or shrink
a.
(x,y) → (5x,y)
b.
1
y)
3
(x,y) → (x,
ANNOUNCEMENTS
 Quiz
Friday
 Homework and Warm ups due
Friday
 Test Tuesday
SIMILAR POLYGONS

Two figures that share:
 Congruent
corresponding angles
 Proportional corresponding sides
WRITING SIMILARITY STATEMENTS
Corresponding Angles must be put in the same
order!
∆ABC~∆DEF
∆ABC~∆FDE - WRONG
THREE POSTULATE THAT PROVE TRIANGLES
SIMILAR
1. AA
(Angle Angle)
2. SSS (Side Side Side)
3. SAS (Side Angle Side)
AA (ANGLE ANGLE)
 If
two angles of one triangle are
congruent to two angles of another
triangle, the triangles are similar
AA PRACTICE
SSS (SIDE SIDE SIDE)
If the three sets of corresponding
sides of two triangles are in
proportion, the triangles are similar
SSS EXAMPLE
Are the two triangles similar?
16
4
20
5
7
28
SAS (SIDE ANGLE SIDE)
If an angle of one triangle is congruent to
the corresponding angle of another triangle
and the lengths of the sides including these
angles are in proportion, the triangles are
similar.
WHICH TRIANGLES ARE SIMILAR? WHY?
HOMEWORK
Pg.
395-396 #1-4, 7, 8,
16-18, 23