Download Grade 2 Lesson: 12.3 Polygons and Angles Reference to English

Grade 2
Lesson: 12.3
Reference to English
Polygons and Angles
Math Standard(s): 2.G.1
Domain: Geometry
Content objective(s):
Language Objective(s):
Students will identify and draw polygons (triangles,
Students will say the shapes and the number of sides, angles and
quadrilaterals, pentagons, and hexagons) and list their
vertices each has.
attributes.
I can name the shapes and say the number of sides, angles and
I can identify and draw polygons (triangles, quadrilaterals,
vertices each has.
pentagons, and hexagons) and list their attributes.
Essential Understanding:
Required Academic Vocabulary for Word Wall:
A shape can be identified by the number of its sides, vertices, or Listen: angle, side, quadrilateral, pentagon, hexagon
angles.
Read: quadrilateral, pentagon, hexagon
Write: quadrilateral, pentagon, hexagon
Speak: sides, angles, vertices, quadrilateral, pentagon, hexagon
Sentence Frame:
Materials:
Additional Lesson Vocabulary:
 Whiteboards, erasers, markers
 Straws
 Pipe cleaners
 Guided and Independent Practice page 390-391
Lesson:
Instructional Time:
Opening: (4 minutes)
T: “You have learned that the faces of some solid figures are plane shapes with 3 or more sides. They are also known as
polygons.”
 Write polygon on the board with plane shapes drawn under it.
T: “Today, you will learn more about polygons and their attributes.”
 Thread a pipe cleaner through two straws.
T: “Let’s pretend that these are two sides of a polygon. I am going to connect them by twisting the ends of the pipe cleaner
together.”
T: “Then I will bend it to form a vertex.”
T: “Thumbs up or down, do I have a polygon with these two sides?”
S: thumbs down.
T: “Two sides together do not make a polygon. If I add another side, do you think I can make a polygon? Whisper what you
think to your neighbor and keep it a secret.”
S: “it will make a polygon.”
 Add another straw and pipe cleaner to the first 2.
T: “I have connected all three sides, do I have a polygon?”
S: “yes.”
T: “Were you right, if we have three sides connected can we make a polygon?”
S: “yes.”
T: “Tell your neighbor the shape it makes.”
S: “a triangle.”
Introduction to New Material (Direct Instruction): (7 minutes)
T: “Let’s describe the attributes of the is triangle. I will trace it on the board.”
T: “This triangle has how many sides?”
S: “three sides.”
T: “Let’s count them together. 1, 2, 3 sides. I will write sides on the board and put a 3 under it.”
 Start drawing a table with the shape on the left (drawn), and then columns for sides, angles and vertices.
T: “So a triangle has 3 sides, how many angles does it have? Tell you neighbor.”
S: “3 angles.”
T: “Let’s count them together. 1, 2, 3 angles. I will write angles on the board and put a 3 under it.”
T: “Lastly, show me with your fingers how many vertices are in this triangle.”
S: will show 3 fingers.
T: “Yes, there are 3 vertices. Let’s count them together, 1,2,3 vertices. I will write vertices on the board and put a 3 under it.”
T: “Question, why is this a triangle? Tell your neighbor.”
S: “it is a triangle because it has 3 sides, 3 angles and 3 vertices.”
T:
S:
T:
S:
T:
S:
T:
“Why is it a triangle?”
“because it has 3 sides, 3 angles and 3 vertices.”
“Do all triangles look the same?”
“no”
“How are all triangles similar?”
“they all have 3 sides, 3 angles and 3 vertices.”
“Yes they do!”
Guided Practice: (5 minutes)
Use the modeling cycle:
Teacher Does:
T: “Now I am going to pass out your whiteboards, markers and erasers.”
 Pass out the whiteboards, markers and erasers.
T: “You and your partner need to figure out how many sides each of the polygons I draw on the board have.”
 Draw a quadrilateral, pentagon and hexagon.
T: “We have a quadrilateral, a pentagon and a hexagon drawn on the board. I need you to draw 3 horizontal lines across your
board.”
T: “Now I need you to draw the quadrilateral in the first box. You and your partner need to write the number of sides, angles
and vertices.”
All Students Do:
S: will draw a quadrilateral and write the number of sides, angles and vertices.
T: “Show me your boards.”
T: “Now turn to your partner and tell them how many sides, angles and vertices the quadrilateral has.”
S: “it has 4 sides, 4 angles and 4 vertices.”
T: “The quadrilateral has (say it with me), 4 sides, 4 angles and 4 vertices.”
T: “Now, do the pentagon with your partner in the second box.”
 Continue the activity with the pentagon and hexagon.
T: “Alright, white off your whiteboards, put them away and go to your desk.”
Independent Practice: (4 minutes)
T: “I am going to pass out guided and independent practice sheets 390 and 391. Let’s do the first one together.”
T: “You need to match the shapes with the names. All the shapes are written on the board with pictures, find them and they will
help you.”
 Teacher will walk around and help students as needed.
S: will answer problem 1
T: “For problems 2 and 3 you need to write down the number of sides, vertices and angles. Then the shape name.”
S: will answer problems 2-3.
T: “Problem 4 you will match the shapes with its name again.”
S: will answer problem 4.
T: “Problems 5 and 6 you need to write draw the shape that is written and then write down the number of sides, vertices and
angles.”
S: will solve problems 5-6
T: “Alright, please turn in your papers and come sit on the carpet.”
Closing: (4 minutes)
 Draw the shapes on the board.
T: “Let’s do a quick review. What shapes is this?”
S: will respond.
T: “How many sides does it have?”
S: will respond.
T: “How many vertices does it have?”
S: will respond.
T: “How many angles does it have?”
S: will respond.
 Go through all shapes learned and reviewed today.
Assessment:
Guided and Independent Practice page 390-391.