# Augmented Reality as a Didactic Resource for Teaching Mathematics
## 1 Introduction
This paper proposes the creation of an application and textbook using AR, for the teaching of polyhedra in the third year of secondary compulsory education, as well as the design of an adapted didactic proposal making use of the resources created. This idea is inspired by the work of [PERSON] and [PERSON] [16], who carried out a huge project for the construction of a complex augmented reality application (Construct 3D) that implements knowledge of geometry with the aim of being used in a classroom. For this, two tools are used: the powerful Unity video game design engine and the software Vuforia. Although this paper is focused on a design for a specific subject, such as mathematics, and for a single teacher to implement it in their classroom, in the case of the design of AR experiences, due to its technical complexity and versatility, it would be positive and advisable to organize a collaborative work between teachers of different subjects [17]. For this, teachers should be assessed on which educational fields and levels AR technology would be the most effective, and what would be the most suitable materials [18]. Following this idea, we propose highly accessible hardware and software that are detailed with sufficient information for AR implementation. AR consists essentially in the superposition of new information to the existing reality using computer devices such as a computer, tablet, or smartphone. When the device detects a certain image, pattern, position on the Earth's surface, etc., it generates the appearance of the new information that is added to the actual existing information. [PERSON] [19] was one of the pioneers in studying this technology. He conceived AR as a combination of elements of reality with virtual elements, interactive in real time and recorded in 3D. In his work, he presents the potentialities of applying this technology in many different fields. These proposals were successful, since currently AR is present in many different areas: commercial and tourism to advertise products and places; education sector; in the design of videogames; architecture and industrial design; military training; for airplane pilots, doctors, astronauts, etc. The types of AR have evolved over the years. A previous work [20] established essentially two types of augmented reality depending on the elements that act as \"activators\" of the information:  
1. Augmented reality based on markers: markers are nowadays the most common way to activate information in augmented reality applications (when the device's camera recognizes any of these markers, digital information emerges). There are two types of markers: flat markers which adopt flat geometric shapes (usually black and white images) that allow a device's software to recognize them (e.g., barcodes and QR (Quick Response), codes) and markerless NFT (natural feature tracking) which uses real-world objects or images to activate information
2. AR geolocated is when the new information is activated by elements of the device that indicate its positioning, such as geolocation (given by GPS (Global Positioning System), GLONASS, Global Navigation Satellite System, etc. ), orientation, device angle, speed, and acceleration. All these data are given by sensors of the device such as the compass, the gyroscope, or the accelerometer. Depending on the degree of complexity that applications use to implement it, there are four types of AR [21]:  
Level 0 (creation of hyperlinks): Applications make use of 2D codes (for example, barcodes or QR codes), which serve as links to other content, so that a marker tracking is not necessary. For example, reading a QR code with our mobile device can take us directly to a web page. Level 1 (augmented reality with markers): In this type, applications use 2D and 3D images as information triggers. When a certain predefined marker is displayed by the camera of the device, the digital information emerges.