Measuring Perimeters
Measure the perimeter of simple 2-D shapes
Lesson
Set out your lesson
“Measuring Perimeters means finding the distance around a simple 2-D shape by measuring each side and adding the lengths. Perimeter is the fence around the shape, not the space inside. We will measure one rectangle, add the sides, then check a fresh shape.”
Bring to the table
- Paper rectangles, squares, or triangles drawn or cut (parent handles scissors)
- A ruler, string, or same-size paper clips for measuring sides
- Pencil for recording side lengths and totals
Extra for the adult
Worked example. A rectangle with sides 4, 2, 4, 2 has perimeter 4 + 2 + 4 + 2 = 12 (same unit). Adding every outside edge measures the perimeter.
Optional challenge. For Measuring Perimeters, measure two rectangles and say which fence is longer and by how much. Optional: draw a shape with a target perimeter and check by measuring.
What to notice. Keep one parent note: shapes measured; side lengths; perimeter totals; support used. A photo of a shape alone cannot record the addition. This session samples a few shapes, not mastery of every perimeter.
Share and support
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Teaching approaches
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1 approach
Measuring Perimeters means finding the distance around a simple 2-D shape by measuring each side and adding the lengths. Perimeter is the fence around the shape, not the space inside. We will measure one rectangle, add the sides, then check a fresh shape.
Spend about 12 minutes measuring perimeters of simple paper shapes by recording side lengths and totals, then checking a new shape.
Family records and proof options
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Learning resources
Extra practice links — they do not replace Gakuva’s teaching approach.
Illustrative Mathematics · Practice link — not the full lesson
Rectangle Perimeter 1
Before you open · source notes
Rectangle Perimeter 1 supports measuring and expressing perimeter. Not every area formula.
Free, no sign-in. A teacher solution is on the same page, so use the student view with your child.
Before you openAsk the learner to find a rectangle perimeter and say what was added.
Opening this link does not save learning or assess mastery.
Source, access and review notes
Public Illustrative Mathematics task page. The .html address responds HTTP 308 to this URL. An anonymous GET of this URL on 2026-11-12 returned HTTP 200 with no login or payment prompt. Where a teacher solution is present, it is on the same page as the student task; this check did not find a separate locked student view. An adult can use the student view section and should not read a solution aloud. Advertising was not observed in the fetched HTML text; that is not a browser, device, or ad-free guarantee. This is a paper or discussion task, not an automatically marked interactive game. Opening the link does not save practice or assess mastery. Diagrams on the page use missing or filename-only alt text, so they are not an accessible image equivalent. Accessibility still depends on an adult describing the picture.
Illustrative Mathematics. “Rectangle Perimeter 1.” Licensed CC BY-NC-SA 4.0. External task; Gakuva does not copy, host, embed, or redistribute it.
CC BY-NC-SA 4.0 — link only
Check understanding
- Measure each side of a rectangle and add the lengths to find the perimeter
- Calculate the perimeter of a regular shape given the side length
- Explain that perimeter is the total distance around a shape
“If your child wants to put a decorative border around a rectangular picture frame 20 cm wide and 30 cm tall, can they work out the total length of border needed?”
Curriculum record
- Type
- Procedural
- Subject
- Mathematics
- Domain
- Measurement
- Age range
- Ages 7–10
Standards