This short video and interactive assessment activity is designed to give fourth graders an overview of quadrilaterals.

This short video and interactive assessment activity is designed to teach third graders about counting the number of basic 2d shapes in a composite figure.

This short video and interactive assessment activity is designed to teach second graders about counting the number of different 2d shapes in a composite figure.

This short video and interactive assessment activity is designed to teach fifth graders about identifying basic 2d shapes in composite figures.

This short video and interactive assessment activity is designed to give fourth graders an overview of reflective symmetry.

This short video and interactive assessment activity is designed to teach second graders about identifying parallel and perpendicular lines.

This short video and interactive assessment activity is designed to teach third graders an overview of quarter-circles and semi-circles.

This short video and interactive assessment activity is designed to teach second graders an overview of quarter-circles and semi-circles.

This short video and interactive assessment activity is designed to give fourth graders an overview of quarter-circles and semi-circles.

This lesson unit is intended to help you assess how students reason about geometry and, in particular, how well they are able to: use facts about the angle sum and exterior angles of triangles to calculate missing angles; apply angle theorems to parallel lines cut by a transversal; interpret geometrical diagrams using mathematical properties to identify similarity of triangles.

This short video and interactive assessment activity is designed to teach third graders an overview of reflective symmetry.

This short video and interactive assessment activity is designed to teach first graders an overview of quarter-circles and semi-circles.

This short video and interactive assessment activity is designed to teach third graders about identifying the properties of squares.

In this Nrich activity students are asked to evaluate data representations based on the book "If the World Were a Village."

The purpose of this task is to help students understand what is meant by a base and its corresponding height in a triangle and to be able to correctly identify all three base-height pairs.

The purpose of this task is to help motivate the usefulness of exponential notation in a geometric context and to give students an opportunity to see that sometimes it is easier to write a number as a numeric expression rather than evaluating the expression, which is an important facet of MP7, Look for and make use of structure.

The goal of this task is to get students to think critically about the effect that changing from one scaling to another has on an image, and then to physically produce the desired image.

The purpose of the task is to help students transition from the informal notion of congruence as "same size, same shape" that they learn in elementary school and begin to develop a definition of congruence in terms of rigid transformations.

This task is designed to give students insight into the effects of translations, rotations, and reflections on geometric figures in the context of showing that two figures are congruent