Room Models

Overview

Students act as architects to design a simple room layout on graph paper at a given scale. They use measurement to calculate and compare perimeter and area, then build scaled plans through peer collaboration.

Learning intentions

WALT (We Are Learning To) design a scaled rectangular room layout on graph paper using measurement tools and geometric reasoning to determine area and perimeter. WALT use vocabulary such as area, perimeter, scale, length, width, and height (as relevant) to explain choices and results. WALT describe how changing dimensions affects both area and perimeter in a real-world style design.

Success criteria

• I can draw a rectangular room to scale on graph paper using correct measurements.
• I can calculate area and perimeter for my room and show the working clearly.
• I can label windows and doors and adjust perimeter/area reasoning appropriately.
• I can explain how increasing or decreasing a dimension changes area and perimeter.

Curriculum links

• Measurement: solve problems involving the area of triangles and parallelograms using established formulas and appropriate units (used as supporting reasoning when considering non-rectangular features).
• Measurement: solve problems involving the volume of right prisms including rectangular and triangular prisms using established formulas and appropriate units (optional “next step” connection to turning layouts into 3D).
• Measurement: identify corresponding, alternate and co-interior relationships between angles formed when parallel lines are crossed by a transversal (linked to accurate straight edges and right angles when drafting).
• Measurement: solve problems involving area of shapes using established formulas and appropriate units (core focus: rectangle-based area/perimeter reasoning).
• General mathematical reasoning: use established representations and units to communicate solutions clearly.

Lesson structure (40 minutes)

1. 0–5 min · Hook (Architect challenge). Teacher displays a simple “room” image (rectangle with 1–2 windows and a door symbol) and asks: “What measurements do we need to draw it accurately on graph paper?” Students quick-write answers: scale, length, width, area, perimeter.

2. 5–15 min · I do (Model drafting + vocabulary). Teacher demonstrates drawing a rectangular room on graph paper:

• Choose a scale (e.g., 1 square = 0.5 m) and write it at the top.
• Use a ruler to measure lengths in centimetres on paper, then convert to metres using scale.
• Draw the room outline as a rectangle; mark windows and door openings with clear labels.
• Teacher explicitly states: perimeter is the total distance around the outside edge of the room, while area is the surface inside the room (number of square units).
• Calculate area (length × width) and perimeter (2(length + width)), with units. Students watch, then copy the working example in their books using the same layout.

3. 15–25 min · We do (Collaborative classroom layout). In pairs, students receive a shared “classroom floor plan card” (rectangular room dimensions + scale + window/door placement). Teacher facilitates:

• Students check measurements together before drawing.
• Students debate one choice: “If we change length but keep width, what happens to perimeter and area?”
• Teacher circulates and prompts correct use of vocabulary (“perimeter is around the outside”; “area is inside”). Whole class shares one pair’s reasoning.

4. 25–38 min · You do (Group architect plans). Students work in groups of 3–4 to create their own scaled room plans on graph paper:

• Room dimensions are given (length and width in metres) and scale is pre-set.
• Must include: outer rectangle, window(s), door label, and written calculations for area and perimeter.
• Peer collaboration requirement: one student is “measurer”, one “drawer”, one “calculator/checker”, and one “communicator” (swap roles if time). Teacher checks success criteria with quick status prompts and correct units.

5. 38–40 min · Exit ticket (Reasoning check). Students complete a short exit ticket: “Your room length increases by 2 m (width unchanged). Explain how your area changes and how your perimeter changes. Use the words area and perimeter.”

Resources

• Graph paper (suitable grid size) and rulers
• Pre-printed architect plan cards (dimensions, scale, window/door placements)
• Example worked model sheet
• Coloured pencils for windows/doors
• Whiteboard/markers
• Timer for “roles” and independent drafting
• Sentence starters on a desk sheet (for vocabulary support)

Assessment

• Formative: observe pair/group drafting accuracy (scale use, correct rectangle proportions, right angles)
• Formative: teacher checks area/perimeter calculations and unit correctness during circulation
• Exit ticket: written explanation linking changed dimensions to both area and perimeter

Differentiation

• Support:
• Provide a partially completed graph outline with scale marked.
• Sentence starters: “My perimeter is… because…”, “My area is… because…”.
• Dyslexia-friendly option: allow students to record calculations using spoken explanation to a teacher or peer, and then write key numbers only.
• Targeted scaffolds:
• Colour-code length and width on the plan before calculation.
• Unit prompts: “metres squared (m²)” for area; “metres (m)” for perimeter.
• Extension (for advanced learners):
• Add a second design option: redraw the same area using different length/width combinations and compare perimeter values.
• Justify which design has the shorter wall length and why (perimeter changes).
• EAL / diverse learners:
• Focus vocabulary posters (area/perimeter/scale/length/width) with simple definitions and visual examples.
• Pair stronger and emerging learners for “measurer/drawer” roles.

Exit ticket success criteria (student-friendly)

• I use the words area and perimeter correctly.
• I state which one increases/decreases and why using length/width reasoning.
• I include at least one calculation step or a clear explanation in words and units.