Guided Lessons

# Trapezoids Are Special

Students will explore geometric shapes by creating a painting of a trapezoid.

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Students will be able to identify and paint trapezoids.

(5 minutes)
• Set up your smartboard or projector to play the Trapezoid and Rectangle Shape Song.
• Play the song for your students. After the song has finished, ask them what they heard.
• Answers might include: "Trapezoids have four sides and one pair of parallel lines." "Rectangles are similar to trapezoids because they have four sides but with different lengths."
• Ask your students what other shapes they saw in the song (cube, cone, cylinder, rectangle). Have the students tell you where those shapes can be found in the world (either using the examples from the song or ones they come up with).
• Explain that today you will be learning about trapezoids and what makes them special.
(5 minutes)
• Draw a trapezoid, square, rectangle, and triangle on the board.
• Ask your students to identify what makes each shape special, or what the defining attributes of each shape is. Answers should include: "Number of sides," "Number of angles," "Corners," or "Vertices."
• Point to the trapezoid and say, “This is a Trapezoid. You can tell it is a trapezoid because it has four sides and four corners. Two of the sides are the same length, one side is short, and the other side is long.”
• Draw a triangle on top of the trapezoid and ask the students what they notice. Point out that a trapezoid looks a lot like a triangle missing the top.
(10 minutes)
• Pass out a handful of pattern blocks to each student.
• Tell the students that they should sort the pattern blocks on the rug in front of them. Don’t tell them how to sort the blocks, allow them to choose their own method.
• Ask for a few volunteers to share how they sorted their blocks. Did they organise by colour, shape, number of sides, or something else?
• Remind students that these are all different attributes of a shape. Some, like colour are called non-defining attributes because a triangle can be blue or yellow and still be a triangle. Some, like number of sides are called defining Attributes. One example of an attribute is triangle always has three sides.
• Explain that students will now get to create their own trapezoid pictures using paint.
(20 minutes)
• Show students how you use the paint to create a large trapezoid on your paper, using your fingers or a paintbrush.
• Check your trapezoid to make sure it has four sides (two the same length, one short, and one long) using a think-aloud format.
• Make your trapezoid into something by adding other shapes to it or images around it. For example, you can turn it into a rowboat.
• Explain that students will get to create their own trapezoid pictures. The only rule is that there needs to be at least one large trapezoid in the picture.

Support

• Use the pattern blocks with a small group of students to identify different shapes by their attributes. Point out the number of sides, corners, and angles of each shape. Have students trace the pattern blocks and label their tracings with the shape attributes and shape name.

Enrichment

• Ask students to label their shape pictures with the name of each shape and the number of sides.
• Have students complete the Basic Shapes worksheet to identify trapezoids.
(10 minutes)
• Circulate around the room during independent work time. Ask students to tell you about their pictures using open ended questions such as, “What shape is that? How do you know? What makes it special? What are its defining/non-defining attributes?”
• Collect shape pictures and assess whether students were able to accurately depict a trapezoid. Display pictures on a wall.
(5 minutes)
• Have students leave their wet paintings on their tables and encourage them to walk around the room for a gallery walk to look at their classmates work.
• Point out a few paintings that clearly show a trapezoid and ask the students to describe their picture and how they know they painted a trapezoid.