Q:

Which figure is the image produced by applying the composition R0,-90 Ry to figure V? A. figure A B. figure B C. figure C D. figure V

Accepted Solution

A:
The figure is going to be rotated by 90 degrees. The direction of the angles in the cartesian plane is always counter-clockwise, so the minus sign means that the figure will be rotated clockwise. Hence, it gets into the first quadrant. Then, it is reflected across the y-axis and thus we get a shape in the 2nd quadrant. It is clear that the new shape has a different orientation from V and thus we get that the answer is shape B.

(The vertical side of the quadrilateral V has to be horizontal in our new figure since the rotation is by 90 degrees and reflections along the axis do not affect whether a line is horizontal or vertical. B Satisfies this, while V does not).