Curriculum / Math / 3rd Grade / Unit 5: Shapes and Their Perimeter / Lesson 5
Math
Unit 5
3rd Grade
Lesson 5 of 16
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Understand perimeter to be the boundary around a two-dimensional shape. Compare perimeters of various polygons using concrete non-standard units.
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.
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Maureen wants to wrap ribbon around her mirror and around her picture frame. Will she need more ribbon for her mirror or her picture frame? Both are shown below.
Outline both shapes below in one color. Then color the inside of both shapes in another color.
a. Which color represents the perimeter of the shape? How do you know? What does the other color represent?
b. Which shape has greater perimeter? How do you know?
c. Which shape has greater area? How do you know?
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. Color the inside of the following shape red. Color the outside edges of the shape blue.
b. Which color represents the perimeter of the shape? How do you know?
c. Use paper clips to measure the perimeter of the shape.
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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Lesson 4
Lesson 6
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
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.
Solve more complex word problems involving perimeter, such as finding a missing side length 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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