The purpose of this activity is to motivate a need for more precise geometric language. Students work with a partner to replicate given geometric images—one partner describes the images and the other draws them, solely based on the verbal descriptions from their partner. Students do this over several rounds, switching roles after two rounds. As students attempt to produce more accurate drawings, they try to fine-tune their descriptions. They notice that more specific language or terminology is needed to better describe the features in the images (MP6).

As students are working, listen for and collect the terms or descriptions that come up often or that effectively help the partner who is drawing replicate the image (for example: horizontal, vertical, point, lines, segment, top, bottom, and so on).

This activity uses MLR2 Collect and Display. Advances: conversing, reading, writing.

• “¿Qué otras palabras o frases importantes deberíamos incluir en nuestra presentación?” // “Are there any other words or phrases that are important to include on our display?”

• Display the chart of terms and these images to facilitate discussion. Annotate them to support students with mathematical terms.

  

  

• As students share responses, update the display, by adding (or replacing) language, diagrams, or annotations.
• Remind students to borrow language from the display as needed.
• “¿Cómo describieron lo que vieron?” // “How did you describe what you saw?” (By describing where the lines start and end, their directions, the distances between them, what they look like—if they look like a familiar shape or letter.)
• “¿Qué palabras o descripciones fueron más útiles cuando describieron las figuras y cuáles fueron menos útiles?” // “What words or descriptions were more helpful when describing the figures and which were less helpful?” (Helpful examples: line, point, straight, corner, triangle, rhombus, vertical, horizontal, middle, top, bottom, left, right. Less helpful examples: here, there, a little bit, pointy, slanted.)
• “¿Qué fue fácil de describir?” // “What was easy to describe?” (Lines that start a corner or the middle of an edge, lines that go left and right or up and down.)
• “¿Qué no lo fue?” // “What was not?” (Lines that cross other lines or that stop at hard-to-describe points.)
• “¿Alguien midió algo o uso medidas? ¿En qué casos podrían haber sido útiles las medidas?” // “Did anyone measure something or use measurements? When might measurements have been helpful?” (When describing distances between lines or the position of a starting point.)

The purpose of this activity is to enable students to notice segments as parts of lines and motivate a need for a term to describe them.

Students are asked to draw multiple lines and to notice shapes that intersecting lines might have created. As they look for familiar shapes or figures in their drawing—polygons, letters, or numbers—their attention shifts from the lines to portions of the lines that make up those figures. Certain sections of the lines now have new significance apart from the lines that contain them. The observations here prepare students to better understand the mathematical definition of line segments.

The Activity Synthesis introduces the term line segment informally. In the next lesson, the meaning of the term, as well as of the meanings of “line” and “point,” will be formalized.

• Display the image on the Task Statement. Invite students to share their drawings and their responses to the discussion questions.
• “¿En qué se parecen sus dibujos?” // “How are your drawings alike?” (They all have long lines. The shapes are made of shorter pieces of the lines. Some of those pieces end in dots. Others are cut off by another line.)
• “¿En qué son diferentes sus dibujos?” // “How are your drawings different?” (The lines made different shapes and letters. Some shapes are made of parts that always end in dots. Others have parts that don’t end in dots.)
• Display the annotated chart from the previous activity.
• “Cada parte de una recta que conforma su figura se llama un segmento de recta o un segmento. Podemos ver dónde empieza un segmento y dónde termina” // “Each part of a line that makes up your shape is called a line segment or a segment. We can see where a segment starts and where it stops.”
• Ask students to point out to their partners some segments in their drawings.
• “Algunos de ustedes han usado la palabra ‘punto’ para describir ciertos lugares de las figuras que dibujaron” // “Some of you have used the word ‘point’ to describe the dots or certain parts of the figures you drew.”
• “¿Cuántos puntos ven marcados en esta recta o segmento de recta? ¿Dónde están?” // “How many points do you see marked on this line or line segment? Where are they?” (I see 3 points marking the top of my 7.)
• “¿Pueden mostrarle a su compañero algunos puntos en las figuras que dibujaron?” // “Can you show your partner some points in the figures you drew?”