What is the circumference?
The perimeter
What is the diameter?
A line going through the centre of the circle
What is the radius?
Half the diameter
What is a chord?
A line which both ends connect to the circumference
What is a tangent?
A line that touches the circle at one point from the outside
What is a sector?
What is an arc?
What are segments?
Areas split by a chord
Which rule is this?
The angle in a semi circle is a right angle.
two radii form a triangle
Which rule is this?
A tangent meets a radius at 90
Which rule is this?
A triangle formed by two radii are isosceles.
All radii are the same length.
What rule is this?
A diameter bisects a chord at a right angle.
Which rule is this?
The angle at the centre is twice the angle at the circumference.
What rule is this?
Angles in the same segment are equal
All triangles drawn from a chord will have the same angle where they touch the circumference
Which rule is this?
Opposite angles in a cyclic quadrilateral = 180o
Which rule is this?
Tangents from the same point are the same length.
also form 2 congruent right angle triangles
Which rule is this?
Alternate segment theorem
angle in the alternate segment are equal
Which rule is this?
Internal intersection
AE x CE = DE x BE
measured from intersection
Which rule is this?
External intersection
MP x MQ = MN x MO
Measured from intersection.
