# Rectangular parallelepiped. Cube

Mastering geometric material cannot be productive if it only involves listening to the teacher’s explanations. Each student should actively participate in the lesson to the best of their abilities, working with the provided geometric materials.

The teacher’s task is to teach students to navigate geometric tasks and develop spatial orientation skills. Each lesson should contribute to the expansion of existing spatial representations.

One method for developing spatial representations in geometry lessons is modeling. Models can be made from paper, cardboard, or wire. The visually impaired student should sit at the first desk of the middle row. It is better to attach a magnifying glass above the desk so the child can perform and see the main points of the practical work. Let’s create a model of a rectangular parallelepiped using a wireframe.

**Question**: What objects give an idea of a rectangular parallelepiped?

**Answer**: Juice carton, box, etc.

**Question**: What shapes make up the surface of a rectangular parallelepiped?

**Answer**: 6 rectangles.

**Question**: How many vertices does a rectangular parallelepiped have?

**Answer**: 8 vertices.

**Question**: How many edges does a rectangular parallelepiped have?

**Answer**: 12 edges.

“Give me a chance to do it myself, and I will learn” (Chinese proverb). Students use wireframes to make a model of a rectangular parallelepiped. After completing the practical work, it’s possible to answer the questions.

## Drawing 1. Model of a rectangular parallelepiped

Working with the model of a rectangular parallelepiped allows the student to more easily navigate the components of this figure.

**Question**: How many dimensions does a rectangular parallelepiped have?

**Answer**: The rectangular parallelepiped has 3 dimensions – length, width, and height.

Concepts such as edge and face are easier for visually impaired students to understand on a model. On the model, students show the top and bottom bases, edges, and faces.

## Drawing 2. Model of a cube

When introducing the concept of a cube, it is important to note the differences between a cube and a rectangular parallelepiped. A cube consists of identical faces and edges, while a rectangular parallelepiped can have different faces and edges.

## Drawing 3. Model of a rectangular parallelepiped

In the lesson using the model of a rectangular parallelepiped, it’s possible to derive the formula for calculating the surface area and the length of the edges. It’s important that students develop skills in constructing geometric figures in every lesson. Visually impaired students should actively participate in the learning process, and teachers should assist them in working with models and drawings.