Question

Use the coordinate rules to rotate triangle ABC 90 degrees counterclockwise around the origin. List the coordinates and draw the image of triangle A'B'C'.

Answer 1

All I really need help with is listing the coordinates.
A(-1,-2) -> A'( _,_ )
B(1, 2) -> B'( _,_ )
C(3,-1) -> C'( _,_ )

Answer 2

The rule for rotating any point (x,y) 90 degrees counterclockwise around the origin is this

(x,y) ---> (-y, x)

Answer 3

For example,

A(-1,-2) -> A'( 2, -1 )

in this case, x = -1, y = -2