Question

Given polygon ABCD with coordinates A(-2,1), B(0,3), C(1,-4), and D(-1,-1), if polygon ABCD is rotated 90° counterclockwise about the origin, then the coordinates of point A' are

Answer 1

@Nnesha you know this?

Answer 2

Im not good at rotations :/

Answer 3

90-counterclockwise \[\huge\rm (x,y) \rightarrow (-y, x)\]
remember this formula for 90 counterclock wise
switch x and y and then change the sign of y

Answer 4

so A would be -2,-1

Answer 5

let's say X( 1,-4)\[(1,-4) \rightarrow (4 ,1)\]

Answer 6

C not X

Answer 7

looks good \o^_^o/

Answer 8

no no

Answer 9

try again remember first switch x and y

Answer 10

so 2,1

Answer 11

1,2*

Answer 12

here is an example \[\huge\rm ( \color{ReD}{5} , \color{blue}{9} ) \rightarrow ( \color{blue}{9},\color{ReD}{ 5}) \rightarrow (\color{blue}{-9},\color{red}{5})\]
first i switched x and y
2nd) i multiplied by new coordinate with negative one (in other words i just changed the sign of new x-coordinate )

Answer 13

ok so its -1,2

Answer 14

(-2,1) first switch x and y

Answer 15

ok so 1,-2

Answer 16

right now change the sign of `new x-coordinate `

Answer 17

(1,-2) now x-coordinate is one

Answer 18

so then thats it or its more?

Answer 19

no that's it
switch x and y
and then change sign of new x-coordinate

Answer 20

ok thank you

Answer 21

so what would be the answer ?

Answer 22

(-2,1) ----- > (??? , ???)

Answer 23

i guess

Answer 24

Given polygon ABCD with coordinates A(-2,1), B(0,3), C(1,-4), and D(-1,-1), if polygon ABCD is rotated 90° counterclockwise about the origin, then the coordinates of point A' are

Answer 25

thats the question

Answer 26

guess ?? hmmm

Answer 27

I mean from what i gather when your switch them then change the signs you get the answer

Answer 28

oky so if A(-2,1) then after rotated 90 counterclockwise
A'(??,???) ??

Answer 29

-1,2

Answer 30

lets do it otherway \[\rm (x,y) \] change sign of y-coordinate\[\rm (x,-y)\]
now switch x and y \[\rm (-y,x)\]

Answer 31

\[(-2,1)\]
try again :=))

Answer 32

1,-2

Answer 33

\[(-2,1)\] first change the sign of y-coordinate in other words ( multiply y-coordinate by negative one )

and then switch x and y

Answer 34

so its 2

Answer 35

\[\rm B(0,3) \rightarrow ( 0 , -3) \rightarrow (-3,0)\] example
i multiplied y-coordinate by negative one ( 0 ,-3)
and then i switched x and y
(-3,0)

Answer 36

-1,-2

Answer 37

\[(-2,1)\] multiply y-coordinate by negative one what would you get ?

Answer 38

yeyayayay!!

Answer 39

thank you

Answer 40

i have one more

Answer 41

ill post it in another thing so i can give you another medal if you want to help

Answer 42

hmm i'm not good at this i'll try not sure