Learning Activity

Finding the Unknown Side of Safety Signs

Subject Area

Mathematics

Grade(s)

3

Overview

This learning activity allows students to explain their thinking to find the unknown side of a polygon when the perimeter is given. Students will solve three different problems where the perimeter is given and knowledge of polygon attributes are needed to find the missing sides. This activity can be used as an assessment or an extension activity after students have mastered how to find the perimeter of a polygon. 

Mathematics (2019) Grade(s): 3

MA19.3.25

Solve real-world problems involving perimeters of polygons, including finding the perimeter given the side lengths and finding an unknown side length of rectangles.

Unpacked Content

UP:MA19.3.25

Vocabulary

  • Attribute
  • Dimension
  • Perimeter
  • Polygon
  • Two-dimensional

Knowledge

Students know:
  • Measurable attributes of objects, specifically perimeter.
  • Strategies for modeling measurement problems involving perimeter.
  • Strategies for representing and computing perimeter.

Skills

The Students are able to:
  • Solve real-world and mathematical problems involving perimeters of polygons.
  • Find the perimeter of a figure given the side lengths.
  • Find an unknown side length of a polygon given the perimeter and one missing side length.

Understanding

Students understand that:
  • Perimeter is measured in length units and is the distance around a two-dimensional figure.
  • If all the sides of a polygon are equal, then the perimeter can be determined by multiplying one side length by the total number of sides.

Phase

After/Explain/Elaborate
Learning Objectives

Learning Objectives

Students will find the unknown side length of polygons when the perimeter is given. 

Activity Details

  1. The teacher will distribute the Unknown Side of Safety Signs Activity Sheet.
  2. The teacher will explain to the students that they will use the Unknown Side of Safety Signs Activity Sheet to solve for the unknown side of safety signs.
  3. The teacher will remind the students they must find the unknown side when given the perimeter. The students will need to use prior knowledge of polygon attributes. (This activity can be completed independently or with partners.)
  4. At the end of class, the teacher can start a class discussion while taking up the activity sheet for assessment purposes.
Assessment Strategies

Assessment Strategies

The teacher will have the students complete the Unknown Side of Safety Signs Activity Sheet for assessment measures.

Background and Preparation

Background / Preparation

  • The teacher will need to make copies of the activity sheet prior to the learning activity. 
  • Students will need background knowledge of polygon attributes and how to find the perimeter of a polygon. 

Digital Tools / Resources

https://docs.google.com/document/d/1gJgU4_u3FvbjasKVGGf5t3eDVPPFvXV3IJt4jIzLiBQ…

Approved Date

Owner (Author)

scarver17
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