Which transformation will be equivalent to rotating a figure 180° counterclockwise?

A) reflecting over the line y = x.
B) reflecting over the line y = -x.
C) reflecting over the x-axis and the y-axis.
D) translating left 3 units and down 5 units.

Respuesta :

If we have given coordinates of the image are in form (h,k).

The resulting coordinates of image rotation of 180° around the origin would be (-h,-k).

We have rule (h,k) ---> (-h,-k).

We can see that x-coordinate is being multiplied by -1 and then y-coordinate is also being multiplied by -1.

Above rule could be break into two parts.

(h,k) ---> (-h,k) ---->  (-h,-k).

We can see in first step, (h,k) ---> (-h,k) is being reflecting over the x-axis and

in second step (-h,k) ---->  (-h,-k) is being reflecting over the y-axis.

Therefore, correct option is C) reflecting over the x-axis and the y-axis.


The transformation which is equivalent to rotating a figure [tex]180^{\circ}[/tex] counterclockwise is reflecting over the [tex]x[/tex]-axis and [tex]y[/tex]-axis. Therefore, the [tex]\fbox{\begin\\\ \bf option (C)\\\end{minispace}}[/tex] is correct.

Further explanation:

Consider a coordinate in the form [tex](a,b)[/tex] where [tex]a[/tex] and [tex]b[/tex] are real numbers.

If [tex]a[/tex] and [tex]b[/tex] are positive then the point [tex](a,b)[/tex] lies in the first quadrant.

If we rotate the coordinate [tex](a,b)[/tex] [tex]180^{\circ}[/tex] counterclockwise then the coordinates become [tex](-a,-b)[/tex].

The coordinate [tex](-a,-b)[/tex] lies in the third quadrant.

If we reflect the coordinate [tex](a,b)[/tex] about the [tex]x[/tex]-axis then the coordinates become [tex](a,-b)[/tex].

The coordinate [tex](a,-b)[/tex] lies in the fourth quadrant.

If we reflect the coordinate [tex](a,-b)[/tex] about the [tex]y[/tex]-axis then the coordinates become [tex](-a,-b)[/tex].

The coordinate [tex](-a,-b)[/tex] lies in the third quadrant.

This implies that rotating a figure [tex]180^{\circ}[/tex] counterclockwise is equivalent to transformation of reflecting over [tex]x[/tex]-axis and reflecting over [tex]y[/tex]-axis.

Option (A)

In option (A) it is given that reflection about the line [tex]y=x[/tex] is equivalent to rotating a figure [tex]180^{\circ}[/tex] counterclockwise.

If we reflect the coordinate [tex](a,b)[/tex] about the line [tex]y=x[/tex] then the coordinates become [tex](b,a)[/tex].

This is not same as rotating the figure [tex]180^{\circ}[/tex] counterclockwise.

Therefore, the option (A) is incorrect.

Option (B)

In option (B) it is given that reflection about [tex]y=-x[/tex] is equivalent to rotating a figure [tex]180^{\circ}[/tex] counterclockwise.

If we reflect the coordinate [tex](a,b)[/tex] about the line [tex]y=-x[/tex] then the coordinates become [tex](-b,-a)[/tex].

This is not same as rotating the figure [tex]180^{\circ}[/tex] counterclockwise.

Therefore, the option (B) is incorrect.

Option (C)

In option (C) it is given that reflection about [tex]x[/tex]-axis and [tex]y[/tex]-axis is equivalent to rotating a figure [tex]180^{\circ}[/tex] counterclockwise.

If we reflect the coordinate [tex](a,b)[/tex] about [tex]x[/tex]-axis and [tex]y[/tex]-axis then the coordinates become [tex](-a,-b)[/tex].

This is same as rotating the figure [tex]180^{\circ}[/tex] counterclockwise.

Therefore, the option (C) is correct.

Option (D)

In option (D) it is given that shifting a point [tex]3[/tex] units left and [tex]5[/tex] units down is equivalent to rotating a figure [tex]180^{\circ}[/tex] counterclockwise.

If we shift the point [tex](a,b)[/tex], [tex]3[/tex] units left and [tex]5[/tex] units down the coordinate is [tex](a+3,b-5)[/tex].

This is not same as rotating the figure [tex]180^{\circ}[/tex] counterclockwise.

Therefore, the option (D) is incorrect.

Therefore, the [tex]\fbox{\begin\\\ \bf option (C)\\\end{minispace}}[/tex] is correct.

Learn more

1. Learn more about the rotation of the triangle   about the origin https://brainly.com/question/7437053.

2. Learn more about when a triangle is rotated  about the origin https://brainly.com/question/2992432.

Answer details:

Grade: High school

Subject: Mathematics

Chapter: Geometry

Keywords: Transformation, rotation, reflection, clockwise, geometry, counterclockwise,  -axis,  - axis, coordinates, graph, origin, line, degrees, translation, symmetry.