Name the type of quadrilateral formed by the following points and give reasons for your answer :

(4, 5), (7, 6), (4, 3), (1, 2)

Find the coordinates of the circumcentre of the triangle whose vertices are (8, 6), (8, -2) and (2, -2). Also, find its circumradius.

Point (0, -7) lies

1. on the x-axis

2. in the second quadrant

3. on the y-axis

4. in the fourth quadrant

Abscissa of a point is positive in

1. I and II quadrants

2. I and IV quadrants

3. I quadrant only

4. II quadrants only