Circle theorems

Question	Answer
Image: ab45ddf3-b005-43f8-b2ca-a71ea647bfc4 (image/png)	The perpendicular bisector of any chord passes through the centre of the circle.
Image: 286d9e5e-88ce-4079-8a97-d95dc938d974 (image/png)	The angle in a semicircle is always 90*.
Image: 474589ea-f3f5-4aaa-9564-7fbd8cfae012 (image/png)	The radius and a tangent always meet at 90*.
Image: 1af8c408-4381-443b-ad6d-b64f19ad34d7 (image/png)	Angles in the same segment are equal.
Image: 81c7aba4-3431-453c-a724-30ae45cf0cbd (image/png)	The angle at the centre is twice the angle at the circumference.
Image: 39e1f11d-c888-4002-a968-e4069da911a1 (image/png)	Opposite angles of a cyclic quadrilateral add up to 180*. (A cyclic quadrilateral is a four-sided shape with each corner touching the circumference of the circle).
Image: 49343972-e8c0-4104-95c4-2d17218decbd (image/png)	The lengths of two tangents from a point are equal.
Image: 102d12cc-08a6-4a2f-bf60-ad9b2ef23b74 (image/png)	Alternate segment theorem.

Resource summary

	Created by Hannah Whitehead almost 11 years ago