Circles Flashcards
What kind of symmetry to circles have?
Circles have both line symmetry and rotational symmetry.
What is a circle?
A circle is a closed plane (2-dimensional) figure. Every point on the circle is the same distance from a fixed point, called the centre.
Arc
A portion of the circumference
Minor arc
An arc that is smaller than a semi-circle
Major arc
An arc that is larger than a semi-circle
Arc symbol
EC with a curve over the top
Diameter
A chord that passes through the centre of the circle
Radius + plural
Plural = radii
A line segment with one endpoint on the centre, the other on the circumference
Centre
All points on the circle are the same distance (equidistant) from a given point in the plane
Central Angle
An angle whose vertex is at the centre and whose sides are radii.
Chord
A line segment with both endpoints on the circumference.
Semicircle
An arc that is half the circle
Segment
Is separated from the rest of the circle by a chord, the space between the circumference and the chord.
