Question 1
A circle has centre (2,6) and radius 10.
Question 1(a)
State the equation of the circle.
Question 1(b)
The circle passes through the point (8, k).
Find the two possible values of k.

Practise coordinate geometry with straight lines, circles, tangents and intersections by forming equations from points and graphs.
A circle has centre (2,6) and radius 10.
State the equation of the circle.
The circle passes through the point (8, k).
Find the two possible values of k.
The equation of a curve is 2x2−kxy+2=0 and the equation of a line is y=p x+3, where k and p are constants.
Given that k=2 and p=11, find the coordinates of the points of intersection of the curve and the line.
(b)Given instead that p=4 ,find the set of values of k for which the curve and the line do not intersect.

The diagram shows the curve with equation x=y2+1. The points A(5,2) and B(2,-1) lie on the curve.
Find an equation of the line A B.
A circle has equation x2+y2+4y−21=0 and a straight line has equation 2 x+y-8=0. The line intersects the circle at two points.
Find the coordinates of these two points of intersection.
The circle has centre C and the two points of intersection are denoted by A and B.
Find the area of the triangle ABC.
The coordinates of points A, B and C are (6, 4), ( p, 7 ) and (14, 18) respectively, where p is a constant. The line A B is perpendicular to the line B C.
Given that p<10, find the value of p.
Find the equation of the tangent to the circle at C, giving the answer in the form d x+e y+f=0, where d, e and f are integers.