3.7(B): Determine the perimeter of a polygon or a missing length when given…
Determine the perimeter of a polygon or a missing length when given perimeter and remaining side lengths in problems.
The Texas Essential Knowledge and Skills (TEKS) for Mathematics outcome 3.7(B) (Geometry and measurement) for Grade 3 says: “Determine the perimeter of a polygon or a missing length when given perimeter and remaining side lengths in problems.” This Fieldbook unit teaches it hands-on, with everyday materials and a printable teacher guide and student sheet for every lesson. Official wording: Texas Essential Knowledge and Skills (TEKS) for Mathematics.
Fence It, Fill It: Area and Perimeter Grades 3–4
Which mat is really the biggest? Does the same fence always hold the same garden? Can the same rug need more edging? Four lessons where students tile, stretch rope and chalk the schoolyard to find out that area and perimeter measure different things.
- Does the same fence always hold the same garden? 50–60 min
Teams stretch the same 12 m rope loop into different rectangles in the schoolyard and find that a fence of the same length can hold 5, 8 or 9 square metres. Students find perimeter by adding the sides, find area by multiplying, and recommend a shape for a school garden.
- How much turf for an L-shaped playground? 50–60 min
Teams chalk a real L-shaped playground in the schoolyard, split it into rectangles to find its area, and discover that cutting a corner off a rectangle takes away area but leaves the perimeter exactly the same. Then they design their own playground to a set of criteria.
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