Curriculum / Math / 3rd Grade / Unit 5: Shapes and Their Perimeter / Lesson 12
Math
Unit 5
3rd Grade
Lesson 12 of 16
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Solve more complex word problems involving perimeter, such as finding a missing side length given perimeter and other side lengths.
The core standards covered in this lesson
3.MD.D.8 — Solve real world and mathematical problems involving perimeters of polygons, including finding the perimeter given the side lengths, finding an unknown side length, and exhibiting rectangles with the same perimeter and different areas or with the same area and different perimeters.
The foundational standards covered in this lesson
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding. This standard is limited to problems posed with whole numbers and having whole-number answers; students should know how to perform operations in the conventional order when there are no parentheses to specify a particular order (Order of Operations).
The essential concepts students need to demonstrate or understand to achieve the lesson objective
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Tasks designed to teach criteria for success of the lesson, and guidance to help draw out student understanding
Gabrielle put a frame around a clock that is in the shape of a regular hexagon. If Gabrielle used 42 centimeters of framing, how long is each side of the clock?
The perimeter of a rectangular index card is 26 inches. Its length is 5 inches. What is its width?
Problem Set
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A task that represents the peak thinking of the lesson - mastery will indicate whether or not objective was achieved
A rectangular notecard has a perimeter of 20 inches. The length of the notecard is 4 inches. What is the width of the notecard?
A square has a perimeter of 12 centimeters. What are the side lengths of the square?
An example response to the Target Task at the level of detail expected of the students.
The Extra Practice Problems can be used as additional practice for homework, during an intervention block, etc. Daily Word Problems and Fluency Activities are aligned to the content of the unit but not necessarily to the lesson objective, therefore feel free to use them anytime during your school day.
Extra Practice Problems
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Help students strengthen their application and fluency skills with daily word problem practice and content-aligned fluency activities.
Lesson 11
Lesson 13
Topic A: Attributes of Two-Dimensional Shapes
Compare and classify polygons.
3.G.A.1
Compare and classify quadrilaterals.
Draw shapes with specified attributes.
Reason about composing and decomposing polygons using tangrams.
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Topic B: Understanding Perimeter
Understand perimeter to be the boundary around a two-dimensional shape. Compare perimeters of various polygons using concrete non-standard units.
3.MD.D.8
Find perimeter of polygons whose sides are marked with unit length marks by counting the unit lengths.
Find perimeter of shapes with all side lengths labeled.
Find perimeter by measuring side lengths in whole number units.
Find perimeter of regular polygons and of rectangles when some side lengths are not given.
Solve word problems involving finding perimeter given the side lengths.
Find side lengths of regular polygons and of rectangles when given perimeter and other side lengths.
Topic C: Distinguishing Between Area and Perimeter
Find rectangles with the same area and different perimeters.
Find rectangles with the same perimeter and different areas.
Solve a variety of word problems involving area and perimeter.
Reason about composing and decomposing polygons with various areas and perimeters using tetrominoes.
3.G.A.1 3.MD.D.8
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