March 21, 2016
Find the area of the regular nonagon. Round to the nearest tenth.
10cm
March 21, 2016
Find the area of the regular nonagon. Round to the nearest tenth.
10cm
March 21, 2016
(11.5) Areas of Similar Figures
Objective: To find areas of similar figures by using scale factors.
To find scale factors or missing measures given the areas of similar
figures.
Why: Models, designs, blue-prints are proportionally related to actual areas.
March 21, 2016
Obj: To find areas of similar figures by using scale factors.
To find scale factors or missing measures given the areas of similar figures.
TRAP ~ BCDE
T
12
9
P
R
B
9
18
8
6
A
E
C
6
12
D
1. What is the scale factor from TRAP to BCDE?
2. Find the perimeter of each figure.
3. What is the ratio comparing perimeters from TRAP to BCDE?
4. Find the area of each figure.
5. What is the ratio comparing the areas from TRAP to BCDE?
March 21, 2016
March 21, 2016
Obj: To find areas of similar figures by using scale factors.
To find scale factors or missing measures given the areas of similar figures.
Theorem: (Areas of Similar Polygons)
If polygons are similar and the
scale factor =
a
b
then the
area ratio =
a2
b2
March 21, 2016
Obj: To find areas of similar figures by using scale factors.
To find scale factors or missing measures given the areas of similar figures.
1.
ABCD ~ RPQS and the area of ABCD
is 48 square inches, find the area of
RPQS.
March 21, 2016
Obj: To find areas of similar figures by using scale factors.
To find scale factors or missing measures given the areas of similar figures.
March 21, 2016
Obj: To find areas of similar figures by using scale factors.
To find scale factors or missing measures given the areas of similar figures.
John is making a scale model of the Pentagon. If the area of his model is
approximately 50 square inches, what is the length of each outer wall of
his model?
March 21, 2016
Obj: To find areas of similar figures by using scale factors.
To find scale factors or missing measures given the areas of similar figures.
HF:
(HR): FUNSHEET(11.5)