Which of the following could be points on the unit circle?(multiple answers)
a. (0.8, 0.6)
b. (1,1)
c.(√(3)/2,1/3)
d.(2/3, √(5),3)
2 Answers

(a) √ [ (0.8)² + (0.6)² ] = 1
(b) √ [ (1)² + (1)² ] = √2 ≠ 1
(c) √ [ {(√3)/2}² + (1/3)² ] = √ [ (3/4) + (1/9) ] ≠ 1
(d) contains a typo.
Only choice (a) has a magnitude of 1 so it lies on the unit circle.

a.