Question

The co-ordinates of the centre of a circle is (3,1) and (6,5) is a point on a circle. The radius of the circle is :

• A. 6
• B. 2
• C. 5
• D. 7

Answer 1

Answer:

C. 5

Radius of the circle = d

$=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

$=\sqrt{6-3)^2+(5-1)^2}$

$=\sqrt{9+16}=\sqrt{25}=5$