90 Degree Rotation

Rotate the point (7,8) around the origin 90 degrees counterclockwise. State the image of the point.

• (-7,-8)

• (8,-7)

• (-8,7)

• (8,7)

Which of the following represents a rotation of 90 degrees clockwise?

• (x,y) -> (-x, -y)

• (x,y) -> (-y, x)

• (x,y) -> (y, -x)

This figure is in quadrant 4. If it is rotated 90 degrees counter clockwise, which quadrant will it end in?

• quadrant 1

• quadrant 2

• quadrant 3

• quadrant 4

This type of reflection is 90 degrees clockwise.

• True

• False

Let A ( -2, 1), B (2, 4) and C (4, 2) be the three vertices of a triangle. If this triangle is rotated about 90° clockwise, what will be the new vertices A' , B' and C' ?

• A'(1,-2) B'(2, -4) C'(-2,4)

• A'(-1,-2) B'(-4,-2) C'(-2,-4)

• A'(2,1) B'(-2,4) C'(-4,2)

• A'(1, 2), B(4, -2) and C'(2, -4)

Which rotations are identified by (x,y) -> ( -y, x) ? Check all that apply.

• 90 degrees Clockwise

• 90 degrees Counterclockwise

• 270 degrees Clockwise

• 270 degrees Counterclockwise

The rule for rotation of 90 degrees clockwise is  
(x, y) --> 

• (y, -x)

• (-y, x)

• (x, -y)

• (-x, y)

The rule for rotation of 90 degrees counterclockwise is  
(x, y) --> _

• (y, -x)

• (-y, x)

• (x, -y)

• (-x, y)

Chose the correct transformation:
(x, y) --> (-y, x)

• Reflection across x-axis

• Reflection across y-axis

• 90 degree clockwise rotation or 270 degree counter clockwise rotation

• 90 degree counter clockwise rotation or 270 degree clockwise rotation

Rotation Rules (clockwise):

90^o rotation: (x, y)→(y, -x)

What are the coordinates for A' after a 90^⁰ rotation clockwise?

• (1, 3)

• (3, 1)

• (3, -1)

• (1, -3)