Question

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

Answer 1

A and D

Explanation:

Unit circle is a circle described by the equation

x^2 + y^2 = 1

We can try each pair and check

A.
`((6)/(7))^2 + ((√(13))/(7))^2 = (36)/(49) + (13)/(49) = (49)/(49) = 1`

B.
`((4)/(3))^2 + ((4)/(5))^2 > ((4)/(3))^2 > 1`

C.
`((1)/(3))^2 + ((2)/(3))^2 = (1)/(9) + (4)/(9) = (5)/(9) < 1`

D.
`((5)/(13))^2 + ((12)/(13))^2 = (25)/(169) + (144)/(169) = (169)/(169) = 1`