Perimeter (shapes with straight edges only)

Find the perimeter of squares, rectangles, triangles, and regular polygons by summing their given side lengths, including converting the answer to a different unit or applying a stated change to each side.

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Te reo Māori terms

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Learning objective overview

Master Teaching Guide coverage for this objective.

Resources

  • Alpha textbook: Perimeter in Ex 23.08, pgs 370 & 371
  • CorbettMaths worksheetQuestions PDF · Answers
  • Beta: Skills in Ex 15.01, 15.04, 15.05, pg 280, 288, 290
  • Beta: Various from chapter 15

Terminology

  • perimeter
  • side
  • polygon
  • regular polygon
  • irregular polygon
  • square
  • rectangle
  • parallelogram
  • triangle
  • kite

Task goals

  • Find the perimeter of a square or rectangle by summing (or doubling and adding) its given side lengths.
  • Find the perimeter of a triangle, given all three side lengths, including scalene, isosceles, and equilateral triangles.
  • Find the perimeter of a regular polygon (pentagon, hexagon, or octagon) by multiplying its side length by the number of sides.
  • Find the perimeter of a rectangle given its length and width in centimetres, and convert the answer to metres.
  • Find the new perimeter of a rectangle after every side length is increased by a stated amount.

Teaching guidance

  • For irregular shapes, students often need to find missing side lengths (using opposite/parallel sides) before summing them to find the perimeter.

Key skills

  • Perimeter
  • Straight edge shapes
  • Basic shapes
  • Composite shapes

Quick stats

  • 81 total questions
  • 3 difficulty levels
  • Answers included