standard_description: Prove theorems about triangles. Theorems include: measures of interior angles of a triangle sum to 180°; base angles of isosceles triangles are congruent; the segment joining midpoints of two sides of a triangle is parallel to the third side and half the length; the medians of a triangle meet at a point.
problem_activity: Narrative
The purpose of this activity is for students to learn stage 3 of the Picture Books center. Students look through picture books and notice and describe shapes they see in the pictures.
Required Materials
Materials to Gather
Picture books
Materials to Copy
Picture Books Stage 3 Recording Sheet
Required Preparation
Each group of 2
–
4 needs at least one picture book that shows a variety of shapes throughout the book.
Launch
Groups of 2
Give each student a recording sheet and each group 2
–
4 picture books.
“We are going to learn a new way to do the Picture Books center.”
“Your group will look through picture books and notice and describe shapes you see in the pictures. On your recording sheet, you will each sketch the shape you see, describe it, and name it.”
Activity
10 minutes: partner work time
Monitor for different shapes students notice.
Activity Synthesis
“What shapes did you find most often?”


aligns: no