Saskatchewan Common Mathematics Assessments
Post Assessment
Outcome: SS9.3 Demonstrate understanding of similarity of 2 -D shapes.
Name: ______________________________________________________
1. The scale factor for an enlargement must be greater than 1. True or false
Level
1
2. A desk has a length 75 cm. The scale factor is . What will be the measurement of the
3
desk?
1
3. A piece of cloth has a length 200cm. It must be made to fit a window that has a scale
factor of 4. What will be the length of the cloth be to fit the window?
2
4. Determine the scale factor of the reduction as a fraction or as a decimal.
3
5. These two pentagons are similar. Determine the value of x.
6. Determine the length of HG.
7. Determine the length of RS in these similar triangles.
8. Find two polygon pairs of corresponding lengths that are proportional. Identify the
scale factor for the reduction.
Level
4
9. Copy the diagram on 1cm grid paper. Draw a reduction of the diagram with a scale factor of
3
.
4
Teacher Section
Teacher Notes: Students will require a calculator and 1cm grid paper.
Question
Indicator
Level
Answer Key:
Answer
1
SS9.3 j
1
True
2
SS9.3 f
2
25cm
3
SS9.3 f
2
800cm
4
SS9.3 c, k
3
1
or 0.5
2
5
SS9.3 l
3
X = 8cm
6
SS9.3 l
3
DG GF

DH HE
4  HG 17.5

4
7
4
4  HG 17.5

4
4
7
4  HG 
17.5  4
7
4  HG  10
4  HG  4  10  4
HG  6
The length of HG is 6 units.
7
SS9.3 l
3
117.6m
8
SS9.3 c, k
4
9
SS9.3 e, i
4
Polygons PR; Scale factor 0f
1
2
Outcome: SS9.3 Demonstrate understanding of similarity of 2-D shapes.
up to Level 1
Description
of Levels:
(based on
Marzano,
2007)
There is a
partial
understanding
of some of the
simpler details
and processes.
Prior knowledge
is understood.
Terminology:
two
dimensional,
Indicators
and
Learning
Targets for
each Level:
Studentfriendly
descriptions
of learning
targets.
Skills:
calculating ratio
up to Level 2
up to Level 3
No major errors or omissions
regarding the simpler details or
processes, but major errors or
omissions regarding the complex
processes may be present.
No major errors or omissions
regarding any of the
information and/or processes
that were explicitly taught.
This is the target level for
proficiency.
(a) Observe and describe 2-D
shapes, relevant to self, family, or
community, that are similar.
(b) Explain the difference between
similarity and congruence of
polygons.
(d) Explain how ratios and
proportionality are related to
similarity of polygons.
(g) Identify and describe situations
relevant to self, family, or
community that involve scale
diagrams and explain the meaning
of the scale factor involved.
(h) Explain how scale diagrams are
related to similarity, ratios, and
proportionality.
(j) Explain how to determine the
scale factor for a given 2-D shape
and an enlargement or reduction of
the shape.
(a)I can observe and describe 2-D
shapes, relevant to self, family, or
community, that are similar.
(b)I can explain the difference
between similar and equality of
polygons.
(d)I can explain how ratios and
proportion are related to similarity
of polygons.
(g)I can identify and describe
situations relevant to self, family,
or community that involve scale
diagrams and explain the meaning
of the scale factor involved.
(h)I can explain how scale
diagrams are related to similarity,
ratios, and proportionality.
(j)I can explain how to determine
the scale factor for a given 2-D
shape and an enlargement or
reduction of the shape.
(c) Verify whether or not two
polygons are similar.
(e) Draw a polygon similar to
a given polygon and explain
the strategies used.
(f) Solve situational questions
involving the similarity of
polygons.
(i) Draw a diagram to scale
that represents an enlargement
or reduction of a given 2-D
shape and explain the
strategies used.
(k) Verify whether or not a
given diagram is a scale
diagram of a 2-D shape and, if
it is, identify the scale factor
for the diagram.
(l) Solve situational questions
involving scale diagrams and
scale factors.
(c)I can prove whether or not
two polygons are similar.
(e)I can draw a polygon
similar to a given polygon and
explain the strategies used.
(f)I can solve situational
questions involving the
similarity of polygons.
(i)I can draw a diagram to
scale that represents an
enlargement or reduction of a
given 2-D shape and explain
the strategies used.
(k)I can confirm whether or
not a given diagram is a scale
diagram of a 2-D shape and, if
it is, identify the scale factor
for the diagram.
(l)I can solve situational
questions involving scale
diagrams and scale factors.
up to Level 4
In addition to
level 3
performance, indepth inferences
and applications
go beyond what
was explicitly
taught.
Problem
combining surface
area and similar
3D objects