Defining attributes of shapes · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

What makes a triangle a triangle

Mathematics · Geometry · ages 6-7
Name ______________________   Date ____________

  1. What makes a shape a triangle?

    • It is colored red
    • It has 3 straight sides and 3 corners
    • It is very small

  2. A triangle always has exactly 3 corners.

    Circle one:   True   False

  3. Count the straight sides on this shape. Type the number.

    Answer: ______________

  4. Mia needs to draw a shape with exactly 3 straight sides. Which shape can she draw?

    • Triangle
    • Circle
    • Square
    • Oval

  5. Ben drew a closed shape with 5 straight sides. All the sides are the same length. What is his shape?

    • Pentagon
    • Hexagon
    • Triangle
    • Quadrilateral

  6. A tiny triangle and a huge triangle both have 3 straight sides and 3 corners. Are they both triangles?

    • No, only the tiny one counts
    • Yes, both are triangles
    • No, only the huge one counts

  7. If you turn a triangle so it points down, it stops being a triangle.

    Circle one:   True   False

  8. A shape with 4 straight sides is always a square.

    Circle one:   True   False

  9. Zara says a shape can't be a triangle because it is huge and purple. What is wrong with her thinking?

    • She forgot that triangles must be red
    • She is using color and size instead of sides and corners
    • She is right, big purple shapes are never triangles

  10. Leo drew a closed shape with straight sides and counted 6 angles. What shape did he draw?

    • Hexagon
    • Pentagon
    • Octagon
    • Square
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Answer key

For grown-ups. Fold this page away before handing over the rest.

What makes a triangle a triangle W1-mt_bfhng6mOuy-s1

  1. It has 3 straight sides and 3 corners · Sides and corners decide the shape's name, not color or size.
  2. True · Each triangle has 3 sides, and 3 corners where the sides meet.
  3. 3 · Go around the shape and count each straight side: 1, 2, 3.
  4. Triangle · A shape with 3 straight sides is called a triangle. The other shapes have a different number of sides.
  5. Pentagon · The number of sides tells you the name. 5 sides makes a pentagon, even when all sides match.
  6. Yes, both are triangles · Size does not decide if a shape is a triangle. Sides and corners do.
  7. False · Turning a shape changes how it looks on the page, but it does not change its sides or corners. A triangle is still a triangle when it points up, down, or sideways.
  8. False · Many shapes have 4 straight sides. A square is special because all 4 sides are the same length and the corners are square corners. Rectangles and rhombuses also have 4 sides.
  9. She is using color and size instead of sides and corners · To check if a shape is a triangle, count its sides and corners. Color and size do not matter.
  10. Hexagon · A closed shape with 6 straight sides and 6 angles is a hexagon.
Worksheet · LightMySky