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: Stage 4: Grade 4 Shapes
Required Preparation
Materials to Gather
Paper
Materials to Copy
Blackline Masters
Shape Cards Grade 4

Narrative
Students lay six shape cards face up. One student picks two cards that have an attribute in common. All students write an attribute that is shared by both shapes. Students get a point if they name an attribute that no other student wrote.
Variation:
Students can draw a shape that has a shared attribute with the given shapes.


aligns: no