Mathematical Emphasis
Investigation 1

• Distinguishing between polygons and shapes that are not polygons
• Drawing polygons
• Recognizing and naming polygons by number of sides

Investigation 2

• Reasoning and communicating about properties of geometric shapes
• Sorting and classifying triangles and quadrilaterals
• Developing vocabulary to describe special triangles and quadrilaterals
• Generating geometric figures from descriptions of their properties
• Estimating and measuring the size of angles and turns

Supplemental Work

• Determining the area of a rectangle
• Determining the area of a corresponding right triangle

Tips For Helping At Home
Questions To Ask:

• What do you need to find out?
• What did you do in class to get started?
• Have you solved similar problems that would help?
• Can you make a drawing (model) to explain your thinking?
• What would happen if…?
• What do you need to do next?
• How do you know your answer is reasonable?
• Has the question been answered?
• Are there any questions you want to ask your teacher?

Helping At Home

• When your child has assignments to work on at home, talk about them together and participate when asked. Prompt your child using the questions above when he or she has difficulty with an activity.
• Play any games sent home that correspond to math work being done in the classroom.
• Look for opportunities to talk about shapes and angles with your child. Rooms and furniture have right angles. Game board spinners have designs that form angles.

Vocabulary Terms

Acute Angle

An angle that is smaller than 90°

Angle

The figure formed when two lines meet

Area

The size a surface covers, measured in square units

Equilateral Triangle

A triangle which has three equal angles and three equal sides

Isosceles Triangle

A triangle with two equal sides and two equal angles

Obtuse Angle

An angle that is larger than 90°

Parallel

Lines which are exactly the same distance apart; they never meet

Parallelogram

A four sided polygon with two pairs of parallel sides

Perpendicular

Lines which intersect and form a right angle

Polygon

A closed, many sided shape with straight sides

Quadrilateral

Any four sided polygon

Right Angle

An angle that is 90°

Right Triangle

A triangle

Scalene Triangle

Triangle which has no equal angles or sides

Triangle

A three sided polygon

Mathematics Vocabulary Web site

Mathematics Strategy—Measuring with Rulers

When working with children to accurately measure with a straight edge, the following ideas should be emphasized:

• Always line up the end of the ruler with the edge of the item being measured.
• When the other edge falls in between the centimeter markings, it is read as 1/10 of a centimeter (3 and 4/10 or 3.4 cm).



• When the other edge falls in between the inch markings, it is read as a fraction of an inch (4 and 3/16 inches, or 5 and ¼ inches).



• If measuring an object that is longer than the length of the ruler, line up the ruler exactly. Do not leave spaces between ruler lengths.

Mathematics Game—Guess My Rule

Materials

Deck of Guess My Rule cards (cards with polygons)

Playing the Game

1. The first player chooses a rule and gives a few examples, putting those shapes that fit the rule in a pile and those that do not fit the rule in another pile. The rule should focus on properties of the shapes (right triangles, or quadrilaterals that are not squares).



2. The second player tries to guess the rule by placing a shape in one of the two piles, depending on whether the player thinks it fits the rule or not.



3. The first player says whether or not the placement is correct.



4. The second player uses this information to eliminate possibilities, come up with new solutions, or revise earlier guesses of what the rule might be. Using this new information, the second player again tries to guess where a particular shape belongs.



5. Repeat steps 3 and 4. The second player can guess a rule if the player thinks he or she has a solution. The first player says whether or not the rule is correct.



6. Play continues until the second player guesses the rule or there are no shapes left to place.

Get to Polygons Sheets (for printing)