Show that the point `(5,5),(6,4),(-2,4)` and `(7,1)` are concylic.Hence find centre and radius of this circle.

Find the centre and radius of the circle (x-5)^2+(y-3)^2=20

Points A(-1, y) and B(5, 7) lie on a circle with centre O(2, -3y). Find the values of y. Hence, find the radius of the circle.

Show that A(4,-1), B(6,0), C(7,-2) and D(5,-3) are vertices of a square.

Show that the equations x^2+y^2-6x+4y-36=0 represents a circle,Also find its centre and radius.

Find the values of a for which points (8,-7,a),(5,2,4) and (6,-1,2) are collinear.

Show that line joining (4,-1) and (6,0) is parallel to line joining (7,-2) and (5,-3).

Show that A(-4,-7), B(-1,2), C(8,5) and D(5,-4) are the vertices of a parallelogram.

Show that abs(frac{z-2}{z-3}) =2, represents a circle find its centre and radius

Show that the line joining the points A(4,8) and B(5,5) is parallel to the line joining the points C(2,4) and D(1,7).