Virginia SOL 3.MG.2

3.MG.2 is a Standards of Learning standard. These are the knowledge and skills expectations under it.

• 3.MG.2.a.i

  describe and give examples of area as a measurement in contextual situations

• 3.MG.2.a.ii

  estimate and determine the area of a given surface by counting the number of square units, describe the measurement (using the number and unit) and justify the ...

• 3.MG.2.b.i

  describe and give examples of perimeter as a measurement in contextual situations

• 3.MG.2.b.ii

  estimate and measure the distance around a polygon (with no more than six sides) to determine the perimeter and justify the measurement

• 3.MG.2.b.iii

  given the lengths of all sides of a polygon (with no more than six sides), determine its perimeter and justify the measurement.

01

What Students Need to Do

Students estimate and find area by counting square units, then record the number and unit. They estimate and find perimeter by measuring or adding side lengths, then justify their method.

02

What Mastery Looks Like

Students choose square units for area and linear units for perimeter. They make reasonable estimates, find accurate measurements, and use a grid, sketch, or equation to explain their answers.

03

Common Misconceptions

Students may confuse the space inside a shape with the distance around it. They may count grid lines instead of squares, omit sides, or label area with linear units such as centimeters.

04

How to Assess It

Give students an L-shape formed by removing the top-right square from a 2-by-3 rectangle on a 1-centimeter grid. Ask them to estimate, calculate, label, and explain its area and perimeter.

1. 01

   Students cover a book with square-centimeter tiles, then wrap string around it and measure the string in centimeters.

2. 02

   Ask, “Would paint or trim use area or perimeter?” Students choose and defend the unit.

3. 03

   Match polygon cards to estimate, area or perimeter equation, and answer cards, then explain one match to a partner.

4. 04

   Draw a small garden plan on grid paper, then calculate square units of soil and units of edging needed.

• 5.MG.2

  The student will use multiple representations to solve problems, including those in context, involving perimeter, area, and volume.

• 3.MG.1

  The student will reason mathematically using standard units (U.S. Customary and metric) with appropriate tools to estimate and measure objects by length, weight...

• 4.MG.3

  The student will use multiple representations to develop and use formulas to solve problems, including those in context, involving area and perimeter limited to...

• 4.MG.1

  The student will reason mathematically to solve problems, including those in context, that involve length, weight/mass, and liquid volume using U.S. Customary a...