Focus Plan
Texarkana Independent School District
GRADING
PERIOD:
Teacher:
2nd 6 Weeks
PLAN CODE:
Winton
Course/subject:
Mathematics
Grade(s):
7
Time allotted
for instruction:
1 – 1 ½ hours
Title:
Are They Similar?
Lesson TOPIC:
Similar Figures
TAKS Objective:
Objective 3: The student will demonstrate an understanding of
geometry and spatial reasoning.
FoCUS TEKS and
Student Expectation:
(6) Geometry and spatial reasoning. The student compares and
classifies shapes and solids using geometric vocabulary and properties.
The student is expected to:
(D) use critical attributes to define similarity
(3) Patterns, relationships, and algebraic thinking. The student solves
problems involving proportional relationships. The student is expected
to:
(B) estimate and find solutions to application problems involving
proportional relationships such as similarity, scaling, unit costs, and
related measurement units
Supporting TEKS and
Student Expectations:
Concepts
Similar Figures
Enduring Understandings/Generalizations/Principles
The student will understand that
Similar figures are figures with the same shape, but not necessarily the
same size.
 Division of Curriculum and Instruction  School Improvement Department  Texarkana Independent School District
I.
Sequence of Activities (Instructional Strategies)
A.
Focus/connections
Materials needed:
 protractors
As students enter the room, place them get in groups of 3 – 4. Hand each member of the group the
worksheet titled Are They Similar?. Have the group use protractors to measure the angles of each
triangle on the worksheet and record their answers. Make sure that the groups have consensus on their
measuring results.
B.
Instructional activities
(demonstrations, lectures, examples, hands-on experiences, role play, active
learning experience, art, music, modeling, discussion, reading, listening, viewing,
etc.)
Discuss how similar figures have to have the same shape, but do not have to be the same size. The
attributes for similar figures are as follows:
 Must have corresponding angles that are congruent.
 Must have corresponding sides that are proportional.
Given those facts, have students determine which of the triangles they have measured are similar. (A &
D, B & H, C & E, F & G)
Draw the following example on the board for your students:
4 mm
8mm
8mm
16mm
Explain that similar figures may also be determined by looking at corresponding sides.
C.
Guided activity or strategy
Have students complete Part A of the Similarity Worksheet individually. Go over the answers with the
students after ample time to complete Part A has been given. Allow time for students to discuss how they
discovered that the triangles were similar.
D.
Accommodations/modifications
Students requiring modifications may be paired with a peer to complete the Guided Activity.
E.
II.
Enrichment
STUDENT PERFORMANCE
A.
Description
Students will complete Part B of the Similarity Worksheet independently.
iii.
B.
Accommodations/modifications
C.
Enrichment
Assessment of Activities
A.
Description
Individual grades may be taken on the Similarity Worksheet.
 Division of Curriculum and Instruction  School Improvement Department  Texarkana Independent School District
B.
Rubrics/grading criteria
Grades may be taken based on the Similarity Worksheet Grading Rubric.


IV.
C.
Accommodations/modifications
D.
Enrichment
E.
Sample discussion questions
Why is it important to be able to determine similar figures?
What real-world applications would the ability to determine similar figures be useful?
TAKS Preparation
A.
Transition to TAKS context
Teacher will lead the class in a discussion of how test problems pertaining to similar figures may look in
test format by putting the TAKS questions below on the overhead/board.
B.
Sample TAKS question
1. Which of the following is NOT true about similar figures?
A. Similar figures always have the same shape.
B. Similar figures always have the same size.
C. Similar figures always have corresponding angles that are equal.
D. Similar figures always have corresponding sides that are proportional.
2.
 Division of Curriculum and Instruction  School Improvement Department  Texarkana Independent School District
V.
Key Vocabulary
Similar figures
VI.
Resources
A.
Textbook
Math Advantage ~ Middle School II
Chapter 16: Ratios, Proportions, and Similarity
 Similar Figures and Scale Factors, pp. 312 – 315
 Proportions and Similar Figures, pp. 317 -319
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
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B.
Supplementary materials
Are They Similar?
Similarity Worksheet
Similarity Worksheet Grading Rubric
C.
Technology
VII.
follow up activities
(reteaching, cross-curricular support, technology activities, next lesson in sequence, etc.)
A good follow-up lesson would be to introduce proportional relationships between similar figures.
VIII.
Teacher NoteS
Online protractor available at: http://www.lawrencegoetz.com/protrace.htm
 Division of Curriculum and Instruction  School Improvement Department  Texarkana Independent School District