Question

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

A. (0.8, -0.6)
B. (1, 1)
C. (√3/2, 1/3)
D. (-2/3, √5/3)

How do I know?

Please explain answer. Thank you!

Answer 1

using general equation of circle "-
\[\large \bf x^2+y^2=r^2\]

Answer 2

and we have given a unit circle,so radius =1 m

Answer 3

right???

Answer 4

yes

Answer 5

so,we get
\[\large \bf x^2+y^2=1\]

Answer 6

now,plug all the values from options and if you get your answer as 1 then that option is CORRECT !!

Answer 7

I'll try it right now...

Answer 8

good !

Answer 9

first try with option A

Answer 10

and tell me what you get ?

Answer 11

0.8^2 + 0.6^2 = 0.28?

Answer 12

1^2 + 1^2 = 2

Answer 13

√3/2^2 + 1/3^2 = 31/36

Answer 14

-2/3^2 + √5/3^2 = 1/9

Answer 15

Did I do something wrong because I did not get 1 yet?

Answer 16

you did wrong in option A

Answer 17

\[\large \bf (0.8)^2+(0.6)^2=0.64+0.36=1=\color{red}{Radius}\]

Answer 18

understood?? @KJ4UTS

Answer 19

Sorry I just checked again a. is 1 but how about my other ones is there more than one answer because it says check all that apply?

Answer 20

I got .28 for option a. because I put -0.6^2 with I thought it says -0.6 in the choices?

Answer 21

I think I got it:

A. (0.8, −0.6) ----> (0.8)² + (−0.6)² = 0.64 + 0.36 = 1
D. (−2/3, √5/3) ---> (−2/3)² + (√5/3)² = 4/9 + 5/9 = 1

Answer 22

correct !!!

Answer 23

good job !!

Answer 24

So its just A. and D.?

Thanks for you time and help!

Answer 25

its my pleasure :)