Circle Theorems

Question	Answer
A tangent (a line touching the circumference) meets the radius at 90 degrees	Image: tangent_meets_radius.gif (image/gif)
The angle at the circumference is half the size of the angle at the center	Image: circle_theorems.gif (image/gif)
Angles in the same segment are equal	Image: angles_in_same_segement.gif (image/gif)
The angle drawn from two ends of a diameter and touching the circumference is 90 degrees	Image: circle_theorem_with_right_angle.gif (image/gif)
Opposite angles in a cyclic quadrilateral (a shape with all 4 sides touching the circumference)add to 180 degrees	Image: cyclic_quadrilateral.gif (image/gif)
Tangents from a point outside the circle are equal in length (icecream theorem :3 )	Image: sequence_tangents_2.gif (image/gif)
The angle between the tangent and chord at the point of contact is equal to the angle in the alternate segment (Alternate segment theorem)	Image: alternate_segment.gif (image/gif)

Resource summary

	Created by lizgracedaisy over 11 years ago