P(-6, 1) and Q(6, 6) are the two ends of the diameter of ...
P(-6, 1) and Q(6, 6) are the two ends of the diameter of a given circle. Calculate the radius.
6.5 units
13.0 units
3.5 units
7.0 units
Correct answer is A
PQ2 = (x2 - x1)2 + (y2 - y1)2
= 122 + 52
= 144 + 25
= 169
PQ = √169 = 13
But PQ = diameter = 2r, r = PQ/2 = 6.5 units