Rectangle PQRS is graphed in the coordinate plane.



Part A


Rectangle PQRS is rotated 90°

counterclockwise about the origin to create rectangle P'Q'R'S' (not shown). What are the coordinates of point R'?


Responses


(−7,6)


(7,6)


(−6,7)


(6,7)


Question 2


Part B


Rectangle PQRS is reflected across the y-axis and then translated down 2 units to create rectangle P''Q''R''S'' (not shown). What are the coordinates of Q''?

Responses


(−6,0)


(6,0)


(−6,−4)


(−6,2)

THE ANSWERS THAT ARE YELLOW IN THE PICTURE ARE WRONG DONT PICK THEM

Rectangle PQRS is graphed in the coordinate planePart ARectangle PQRS is rotated 90 counterclockwise about the origin to create rectangle PQRS not shown What ar class=
Rectangle PQRS is graphed in the coordinate planePart ARectangle PQRS is rotated 90 counterclockwise about the origin to create rectangle PQRS not shown What ar class=

Respuesta :

Answer:

  Part A:  (b) (7, 6)

  Part B:  (c) (-6, -4)

Step-by-step explanation:

You want the coordinates of points of rectangle PQRS that have been subject to rotation, reflection, and translation.

A. Rotation

Rotation 90° CCW is accomplished by the transformation ...

  (x, y) ⇒ (-y, x)

Then point R gets rotated to ...

  R(6, -7) ⇒ R'(7, 6)

B. Reflection, translation

Reflection across the y-axis changes the sign of the x-coordinate:

  (x, y) ⇒ (-x, y) . . . . . . reflection in the y-axis

Translation adds the translation amount to the relevant coordinate:

  (x, y) ⇒ (x, y -2) . . . . translation down 2 units

Together, the effect on point Q is ...

  (x, y) ⇒ (-x, y -2)

  Q(6, -2) ⇒ Q''(-6, -4)

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Additional comment

You can figure the transformation related to rotation by considering "where did it come from?"

If a point ends up on the x-axis after a rotation of 90° CCW, it had to come from the -y axis.

If a point ends up on the y-axis after a rotation of 90° CCW, it had to come from the +x axis.

These observations can be written as the transformation ...

  (x, y) ⇒ (from -y, from +x) = (-y, x) . . . . . . rotation 90° CCW

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