Wentzville School District
Curriculum Development Template
Stage 1 – Desired Results
Unit Four – Ratios, Proportions, and Similar Figures
Unit Title: Ratios, Proportions, and Similar Figures
Course: Pre-Algebra
Brief Summary of Unit: Students will learn to identify and represent proportional relationships. In addition, students
will use the properties of proportions to make conversions between units and unit rates. Finally, students will solve
real-world problems, such as reducing or enlarging a figure, using ratios and proportions using multiple strategies.
Textbook Correlation: Glencoe Math Accelerated Chapter 5 including the Similar Figures Lab
Time Frame: 3.5 weeks
WSD Overarching Essential Question
Students will consider…
●
●
●
●
●
●
●
●
●
●
●
●
How do I use the language of math (i.e. symbols,
words) to make sense of/solve a problem?
How does the math I am learning in the classroom
relate to the real-world?
What does a good problem solver do?
What should I do if I get stuck solving a problem?
How do I effectively communicate about math
with others in verbal form? In written form?
How do I explain my thinking to others, in written
form? In verbal form?
How do I construct an effective (mathematical)
argument?
How reliable are predictions?
Why are patterns important to discover, use, and
generalize in math?
How do I create a mathematical model?
How do I decide which is the best mathematical
tool to use to solve a problem?
How do I effectively represent quantities and
relationships through mathematical notation?
WSD Overarching Enduring Understandings
Students will understand that…
●
●
●
●
●
●
●
●
●
Mathematical skills and understandings are used
to solve real-world problems.
Problem solvers examine and critique arguments
of others to determine validity.
Mathematical models can be used to interpret and
predict the behavior of real world phenomena.
Recognizing the predictable patterns in
mathematics allows the creation of functional
relationships.
Varieties of mathematical tools are used to
analyze and solve problems and explore concepts.
Estimating the answer to a problem helps predict
and evaluate the reasonableness of a solution.
Clear and precise notation and mathematical
vocabulary enables effective communication and
comprehension.
Level of accuracy is determined based on the
context/situation.
Using prior knowledge of mathematical ideas can
help discover more efficient problem solving
●
●
How accurate do I need to be?
When is estimating the best solution to a
problem?
●
strategies.
Concrete understandings in math lead to more
abstract understanding of math.
Transfer
Students will be able to independently use their learning to…
●
●
●
Read and analyze maps and blueprints.
Use proportional reasoning to make sound financial decisions.
Use proportional reasoning to find appropriate conversions (dosages, recipes, time, etc.)
Meaning
Essential Questions
Understandings

How can you identify and represent
proportional relationships?

A ratio is a comparison of two numbers or
two measurements.

How are unit rates useful in everyday, realworld contexts?

A unit rate shows relationship between two
different units.

How can graphs, tables, and equations assist
in calculating and predicting unit rates?

Proportions are mathematical sentences
identifying equivalent ratios.

How can I determine a unit rate from a table or
graph?

Once you determine a relationship between
two units, that relationship can be used to
determine unknown quantities.

What strategies can I use to determine if two
quantities are in a proportional relationship?

Tables, graphs, equations, and diagrams can
all be used to represent and/or analyze a
proportional relationship.

A graph, table, or equation can be used to
determine if a relationship is proportional..

Scale is the relationship between an actual
object and a drawing or model of that object.

Scale can be used to increase or decrease
the dimensions of any geometric figure.

Scale drawings can be used to find real
lengths and areas.

What role does an equation play in
determining proportional relationships?

How can cross products be used to help solve
a proportion?

How can a proportion be set up to represent a
real-world context?

What other methods are available to solve a
proportion?


How and why do we use scale drawings in the
real world?

What are different ways we can use ratios
(scale, conversion factor, etc.) to find unknown
measurements?
A scale factor greater than 1 will result in an
enlargement; a scale factor less than 1 will
result in a reduction.

Properties of operations on fractions extend
to complex fractions.

How do I apply properties of rational numbers
to manipulate complex fractions?

What makes a fraction complex?

What are real world applications of rational
numbers, including complex fractions?
Acquisition
Key Knowledge

















Complex fraction
Unit rate
Constant of proportionality (unit rate)
Ratio
Proportion / Proportionality / Proportional
Relationship
Equivalent Ratios
Scale factor
Scale drawing
Similar figures
Congruent
Corresponding parts
Cross products
Dimensional analysis
Indirect measurement
Rate
Scale
Scale model
Key Skills

Write ratios as fractions in simplest form.

Simplify ratios involving measurements.

Write and solve equations for real-world
problems (proportions).

Compute unit rates associated with ratios of
fractions (this is a complex fraction).

Calculate and/or predict a unit rate from
graphs, tables, and equations.

Write an equation to represent a proportion
based on a graph or table

Identify proportional relationships and nonproportional relationships using graphs and
tables.

Convert rates using dimensional analysis

Solve problems involving indirect
measurement using shadow reckoning and
surveying methods.

Create a graph based on a table or equation

Apply various strategies to determine
proportionality of two ratios

Use cross products to solve a proportion.

Reproduce a geometric figure at a different
scale.

Use a scale factor and the method of their
choice (proportions, equivalent fractions) to
compute actual lengths and areas.

Use a scale factor to produce a scale model or
drawing.
Standards Alignment
MISSOURI LEARNING STANDARDS
Apply and extend previous understandings of operations with fractions to add, subtract, multiply, and divide rational
numbers.
(7.NS.3) Solve real-world and mathematical problems involving the four operations with rational numbers.
(Computations with rational numbers extend the rules for manipulating fractions to complex fractions.)
Analyze proportional relationships and use them to solve real-world and mathematical problems.
(7.RP.1) Compute unit rates associated with ratios of fractions, including ratios of lengths, areas and other
quantities measured in like or different units. For example, if a person walks ½ mile in each ¼ hour, compute the
unit rate as the complex fraction ½ / ¼ miles per hour, equivalently 2 miles per hour.
Analyze proportional relationships and use them to solve real-world and mathematical problems.
(7.RP.2) Recognize and represent proportional relationships between quantities
a. Decide whether two quantities are in a proportional relationship, e.g., by testing for equivalent
ratios in a table or graphing on a coordinate plane and observing whether the graph is a straight line
through the origin.
b. Identify the constant of proportionality (unit rate) in tables, graphs, equations, diagrams, and verbal
descriptions of proportional relationships.
c. Represent proportional relationships by equations. For example, if total cost t is proportional to the
number n of items purchased at a constant price p, the relationship between the total cost and the
number of items can be expressed
as t = pn.
d. Explain what a point (x, y) on the graph of a proportional relationship means in terms of the
situation, with special attention to the points (0, 0) and (1, r) where r is the unit rate.
Analyze proportional relationships and use them to solve real-world and mathematical problems.
(7.RP.3) Use proportional relationships to solve multistep ratio and percent problems.
Examples: simple interest, tax, markups and markups and markdowns, gratuities and commissions, fees, percent
increase and decrease, percent error.
Draw, construct, and describe geometrical figures and describe the relationship between them.
(7.G.1) Solve problems involving scale drawings of geometric figures, including computing actual lengths and
areas from a scale drawing and reproducing a scale drawing at a different scale.
MP.1 Make sense of problems and persevere in solving them.
MP.2 Reason abstractly and quantitatively.
MP.3 Construct viable arguments and critique the reasoning of others.
MP.4 Model with mathematics.
MP.5 Use appropriate tools strategically.
MP.6 Attend to precision.
MP.7 Look for and make use of structure.
MP.8 Look for and express regularity in repeated reasoning.
SHOW-ME STANDARDS
Goals:
1.1, 1.4, 1.5, 1.6, 1.7, 1.8
2.2, 2.3, 2.7
3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8
4.1, 4.4, 4.5, 4.6
Performance:
Math 1, 5