Mathematics (Core)Exam code: 0580

Symmetry and Shapes

Geometry

PractiseFlashcards

The terms to know

  • Centre: the point every part of the circle is the same distance from
  • Radius: a line from the centre to the edge; the plural is radii
  • Diameter: a line right across through the centre, equal to twice the radius
  • Circumference: the distance all the way round the edge
  • Chord: a straight line joining two points on the circumference; a chord through the centre is a diameter
  • Arc: part of the circumference
  • Sector: the slice between two radii and an arc
  • Segment: the region cut off between a chord and an arc
  • Tangent: a straight line touching the circle at exactly one point
  • Semicircle: half a circle, cut off by a diameter
  • Confusing the radius with the diameter is a frequent error in circle calculations, so check which one a question gives
A circle with centre O labelled with each of its parts: a radius from O out to B, a diameter right across through O, a chord cutting off a segment which is shaded, the sector OAB shaded between two radii, the arc from A to B, and a tangent touching the circle at one point
Source: Properties of 2D shapes by Save My Exams

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