Definitions Flashcards
Diameter
Straight line through centre of circle
Radius
Straight line from centre of circle to edge
(half diameter)
Centre
Middle of circle
(where point of compass would go)
Tangent
Straight line that ‘‘just touches’’ the circle at one point
Circumference
The distance around a circle
(the perimeter)
Chord
Straight line that goes through the circle, BUT not through the centre
Segment
An area produced by drawing a chord (uncivilised slice of pizza)
major=bigger
minor=smaller
Sector
the area between two radii
(like a slice of pie/pizza)
Arc
A partial bit of the circumference
major=bigger
minor=smaller
(often between two radii, like the crust if a pizza)
Subtended Angle
An angle within a circle is created by two chords meeting at a point on the circumference. The diagrams below show the angle subtended by arc AC from point B for two different circles.
Alternate Angles
Alternate Interior Angles are a pair of angles on the inner side of each of those two lines but on opposite sides of the transversal.
(doesn’t have to be two parallel lines)
Congruence
Identical shapes (size, angles, sides)
Isosceles triangle
Triangle with two angles and sides that are the same
Solve
Find the value of the unknown, normally a letter (x)
Radii
Plural of radius, meaning two or more
Sum
means to add together
Semi circle
half a circle
Right angle
a 90 degree angle
Quadrilateral
any four sided shape (where all sides are straight lines)
Cyclic quadrilateral
A four sided shape where each vertex lies on the circumference
vertex
the corner of a 2d shape, where two lines meet
Origin (on graph)
The centre of the graph, co-ordinate (0, 0)
Gradient
the rate of change, how steep a line is
perpendicular
lines are perpendicular if they meet at 90 degree angles
parallel
lines are parallel if they never meet
