Question

Which of the following could be points on the unit circle?

Answer 1

There is more than one answer

Answer 2

do you know the distance formula for two points?

Answer 3

and if you do, what distance does a point need to have from the origin in order to be a element of the unit circle?

Answer 4

Not really...

Answer 5

\[\large d= \sqrt{(x_2-x_1)^2+(y_2-y_1)^2} \]

Answer 6

A point (x,y) is on the unit circle if and only if
\[
x^2 + y^2 =1
\]

Answer 7

D is one.

Answer 8

and A the other one

Answer 9

A is one

Answer 10

Thank you @eliassaab and @spacelimbus for the formulas!