Circles

Question 1

What is the equation of a circle?

Answer 1

(x - a)^2 + (y - b)^2 = r^2

Question 2

What size is the angle in a semicircle?

Answer 2

Always 90 degrees

Question 3

What size is the angle at the circumference of a circle compared to at the centre?

Answer 3

The angle at the circumference is half the angle at the centre

Question 4

What do opposite angles in a cyclic quadrilateral add up to?

Answer 4

180 degrees

Question 5

Angles subtended by the same arc, or chord, are what?

Answer 5

Angles subtended by the same arc or chord are equal in size

Question 6

Tangents which meet at the same point are what in length?

Answer 6

Tangents from the same point are equal in length

Question 7

The angle between a tangent and a radius is what?

Answer 7

90 degrees

Question 8

The line joining an external point to the centre of a circle does what to the angle between the tangents to the circle from that external point?

Answer 8

The line joining an external point to the centre of a circle bisects the angle between the tangents to the circle from that external point?

Question 9

A radius bisects a chord as long as it is what?

Answer 9

A radius bisects a chord as long as it is perpendicular to the chord