Answer:
C and D
Explanation:
Mathematically, a unit circle is one in which the value of the radius is 1 unit
Generally, for a unit circle we have it that;
r^2 = x^2 + y^2
where (x,y) represents the coordinates of a point on the unit circle
But from above, r = 1
Thus:
x^2 + y^2 = 1
Looking at option C, by squaring each coordinate, we have
(6/7)^2 = 36/49 and the second as 13/49
by adding both, we have
36/49 + 13/49 = 49/49 = 1
Thus, we have this as a coordinate on the unit circle
For the last option;
(5/13)^2 = 25/169 and (12/13)^2 = 144/169
Adding both, we have;
25/169 + 144/169 = 169/169 = 1
So this is also a point on the unit circle