Download A triange`s angles are in the ratio 2:3:4. What are the measures of

January 27, 2016
A triange's angles are in the ratio 2:3:4. What are the measures of the
angles?
January 27, 2016
(7.2) Similar Polygons (7.3) (Similar Triangles)
Objective: To use proportions to identify similar polygons.
To solve problems using properties of similar polygons.
To prove Triangles Similar and find missing parts.
Why: Enlarging/Reducing objects is important in many
applications (logos, signs, blueprints, etc)
January 27, 2016
Obj: To use proportions to identify similar polygons.
To solve problems using properties of similar polygons.
To prove triangles similar and find missing parts.
Similar Polygons:
ABCD ~ WXYZ
B
W
Z
A
X
C
Y
D
Find n, x, and y.
ABCD ~ WXYZ
B
A
12
(y+34)o
83o
Z
9
C
x
D
Are the figures similar? Explain.
6 W
(3y13) o
10
Y
X
3n-1
January 27, 2016
Obj: To use proportions to identify similar polygons.
To solve problems using properties of similar polygons.
To prove triangles similar and find missing parts.
January 27, 2016
Obj: To use proportions to identify similar polygons.
To solve problems using properties of similar polygons.
Ways to Prove Triangles Similar:
To prove triangles similar and find missing parts.
1. Angle-Angle (AA) Similarity Postulate:
If two angles of one triangle are congruent to two angles of
another triangle, then the triangles are similar.
F
C
If
then ABC~ DEF
A
B
E
D
2. Side-Side-Side (SSS) Similarity Theorem:
If corresponding side lengths in two triangles are proportional,
then the triangles are similar.
F
C
A
B
AB
If
DE
=
BC
EF
=
E
D
AC
then
FD
ABC~ DEF
3. Side-Angle-Side (SAS) Similarity Theorem:
If 2 sides of one triangle are proportional to 2 sides of another
triangle, and their included angles are congruent, then the
triangles are similar.
F
C
A
If
AC
DF
B
=
AB
DE
E
D
and
A =
D
then
ABC~ DEF
January 27, 2016
Obj: To use proportions to identify similar polygons.
To solve problems using properties of similar polygons.
To prove triangles similar and find missing parts.
January 27, 2016
Obj: To use proportions to identify similar polygons.
To solve problems using properties of similar polygons.
To prove triangles similar and find missing parts.
January 27, 2016
Obj: To use proportions to identify similar polygons.
To solve problems using properties of similar polygons.
To prove triangles similar and find missing parts.
First, prove
ABE ~
ACD. Then find x and y.
January 27, 2016
Obj: To use proportions to identify similar polygons.
Find x.
To solve problems using properties of similar polygons.
To prove triangles similar and find missing parts.
January 27, 2016
Obj: To use proportions to identify similar polygons.
To solve problems using properties of similar polygons.
HW:
To prove triangles similar and find missing parts.
(HR): (7.2) Pg.474: 19, 23, 24, 36, 37
(7.3) Pg.483: 9, 11, 12, 17, 18, 23