Circle Theorems

Question 1

Alternate Segment Theorem

Answer 1

The angle that lies between the tangent and a chord is equal to the angle subtended by the same chord in the alternate segment.

Question 2

Subtended

Answer 2

The angle that is formed when two lines meet together at one point

Question 3

Angle at the centre theorem

Answer 3

The angle at the centre of the circle is twice the angle at the circumference of the circle when standing on the same arc.

Question 4

Angles in the same segment

Answer 4

Angles in the same segment are equal.

Question 5

Angles in the semi-circle

Answer 5

Angles in a semi-circle is always 90 degrees.

Question 6

Cyclic quadrilateral

Answer 6

The opposite angles in a cyclic quadrilateral total to 180 degrees

Question 7

Tangent to a circle

Answer 7

Tangents that meet at the same point from a point outside the circle are equal in length.

Question 8

Tangent and radius

Answer 8

the angle between a tangent and a radius is always 90 degrees.