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Flashcards in Circle Theorems Deck (9)
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1
Q

State the rule for:

An angle at the point of an arrow head is half the angle enclosed at the centre

A

The angle at the centre of a circle is twice the angle at the circumference that is subtended by the same arc

2
Q

cyclic quadrilateral

A

The sum of the opposite angles of a cyclic quadrilateral is 180

3
Q

Radius and chord

A

A radius bisects a chord at 90°

4
Q

Right angle triangle in a semi circle

A

every angle at the circumference of a semicircle that is subtended by the diameter of the semicircle is a right angle

5
Q

Tangent and radius

A

A tangent to a circle is perpendicular to the radius drawn to the point of contact

6
Q

Tangent length

A

Tangents to a circle from an external point to the points of contact are equal in length

7
Q

Tangent angles

A

A line joining an external point to the centre of the circle bisects the angle between the tangents

8
Q

Angles on the circumference are the same if the lines come from the same point

A

Angles subtended at the circumference in the same segment of a circle are equal

9
Q

The angle between a tangent and a chord through the point of contact is equal to the alternate segment

A

Alternate segment theorem