### Geometry

In this unit, students will explore how two-dimensional figures and their images are related under translations, rotations, reflections and dilations. Similarity and congruence will also be investigated. Students will identify the relationships between angles formed by intersecting lines and angles created when a transversal intersects parallel lines. Students will solve problems involving the area and circumference of a circle and investigate two-dimensional cross-sections of three-dimensional figures. Students will solve real-world problems involving surface area and volume of cubes, right prisms, cones, cylinders and spheres. Students will explore the Pythagorean Theorem and its converse.

This unit was developed from the Common Core State Standards. For more information download the unit guide (on the right) where the specific content standard is identified. There may be other CCSS that align to the activities as well that are not referenced on the guide.

### Middle Grades Math: Geometry Activities

Title Type

#### The Mailbox

Student will use the Measurement tools found in the Geometry menu options or model the image using functions on the Graph page

• 32

#### Reflections and Rotations

Students will reflect figures over the x- and y-axes. By studying what happens to the coordinates of the pre-image and image points, they will write rules for reflecting points over the axes. Students will then rotate figures about the origin, in both clockwise and counterclockwise directions. Again, they will study what happens to the coordinates of the pre-image and image points to write rules for reflecting points 90° and 180° about the origin.

• 2571

#### Scaling the Geometry

This lesson involves scale drawings of actual images on the TI-Nspire handheld.

• 2229

#### Slices

This lesson involves exploring the shapes formed from 3D figures cut by a horizontal and/or a vertical plane. • Compatible TI Technologies: TI-Nspire™ CX Handhelds, TI-Nspire™ Apps for iPad®, TI-Nspire™ Software

• 2327

#### Getting "A-Round" Area

This lesson involves using sectors of a circle to form a parallelogram and, from this shape, investigating the area formula for a circle.

• 2330

#### Angles for a Solution

This lesson involves looking at several sketches of intersecting lines and determining the measures of the missing angles using the facts about supplementary, complementary, vertical, and adjacent angles.

• 2409

#### We've Got You Covered: 2D Area

This lesson involves using the geometry tools to measure the area of two-dimensional shapes from the faces of three-dimensional objects they see in pictures taken outside of the classroom.

• 2284

#### The Pentagon Problem

This activity provides a simple, virtual "geoboard" that allows students to manipulate the polygon displayed on a unit grid. The grid squares provide a visual means of finding area.

• 2134

#### Transformers in the Classroom

This lesson involves digitizing an image and transforming it on a graph.

• 2147

This lesson involves examining a visual proof of the Pythagorean Theorem and supporting what happens geometrically.

• 2502

#### Volume Relationships

This lesson involves the volume formula for cylinders, cones, and spheres.

• 2640

#### Exploring Areas of Irregular Polygons

Explore different ways to find areas of irregular polygons using the three basic shapes of rectangles, parallelograms, and triangles.

• 6741

#### Creating Parallel Lines and Transversals

Create a pair of parallel lines cut by a transversal and investigate the relationships among the angles that are created.

• 7301