Circle Theorems

Question 1

A DIAMETER//passing through centre// to make two points on circle which join to make another point.

Answer 1

Angles at the circumference in a semi circle are always at a right angle

Question 2

Two points on circle joint at centre and at one other point on the circle

Answer 2

The angle at the centre of the circle is twice the angle at the edge that comes from the same arc.

Question 3

Two points on the circle join to make another two points on the circle

Answer 3

Angles in the same segment from the same chord are equal.

Question 4

A quadrilateral//all four point touching circle

Answer 4

Opposite angles in a cyclic quadrilateral sum to 180 degrees

Question 5

A tangent meets the circle at the radius

Answer 5

A tangent will always meet a radius at 90 degrees.

Question 6

PACMan

Answer 6

Tangents from an external point to the point of contact are equal lengths

Question 7

A triangle in a circle upon a tangent

Answer 7

Angles in alternate segments are equal