Circles and loci

Question 1 of 10

Find the equation of the circle with diameter joining (1, 2) and (5, 6).

Question 2 of 10

The radius of the circle x² + y² − 6x + 8y = 0 is

Question 3 of 10

The locus of points equidistant from two fixed points A and B is

Question 4 of 10

What is the equation of the circle with centre (0, 0) and radius 3?

Question 5 of 10

The locus of points P such that PA = 2PB, where A = (0, 0) and B = (3, 0), is a

Question 6 of 10

The locus of points equidistant from two fixed points is

Question 7 of 10

The locus of points 4 cm from a fixed point is

Question 8 of 10

Find the length of the tangent from (7, 1) to the circle x² + y² = 25.

Question 9 of 10

Find the centre of the circle (x + 1)² + (y − 4)² = 16.

Question 10 of 10

Find the equation of the circle with centre (0, 0) and radius 5.