Answer:
Points A and B are not on the unit circle.
Step-by-step explanation:
Recall that a "unit circle" has a radius of 1, and so if x² + y² ≠ 1, the point is not on a unit circle.
In A we apply the Pythagorean Theorem as follows: 1² + 1² = 2 ≠ 1.
Therefore, point (1, 1) is not a point on the unit circle.
In B: if we square the x and y components and add these squares together, we get 3/4 + 1/9, which does not equal 1. Point not on unit circle.
In C, we get 4/9 and 5/9, which eqals 1. This point C lies on the unit circle.
In D, we get 0.64 + 0.36 = 1, so this point does lie on the unit circle.
Thus: not on unit circle: A(1, 1), B(√3/2, 1/3)
On unit circle: D(0.8, -0.6), C(-2/3, √5/3)
