A triangle is dilated by a scale factor of 1/5 and then rotated 90 degree clockwise about the origin. Why is the image similar t
o the pre-image? Check all that apply. A) The corresponding sides of the triangles are congruent.
B) The corresponding angles of the triangles are congruent.
C) The corresponding sides of the image are 5 times as long as those of the pre-image.
D) The image is a reduction of the pre-image.
E) Neither the dilation nor the rotation change the shape of the triangle.
F) The rotation reduces the size of the triangle.
<u><em>Answers:</em></u> The corresponding angles of the triangles are congruent The image is a reduction of the pre-image Neither the dilation nor the rotation change the shape of the triangle
<u><em>Explanation:</em></u> <u>For shapes to be similar:</u> 1- there should be a ratio between the sides 2- angles in first shape should be congruent to angles in second shape
Now, a scale factor of 0.2 means that the sides of the image are 0.2 of the length of the original shape. However, angles are not changes
<u>Let's check the choices:</u> <u>1- </u><span><u>The corresponding sides of the triangles are congruent:</u> This option is incorrect as dilation changes the lengths of the sides
<u>2- </u></span><span><u>The corresponding angles of the triangles are congruent:</u> This option is correct as neither dilation nor rotation alters the measures of the angles
<u>3- </u></span><span><u>The corresponding sides of the image are 5 times as long as those of the pre-image:</u> This option is incorrect as the sides of the image are only 0.2 times as long as those of the pre-image
<u>4- </u></span><span><u>The image is a reduction of the pre-image:</u> This option is correct as the sides of the image are 0.2 times those of the pre-image which means that the shape is reduced
<u>5- </u></span><span><u>Neither the dilation nor the rotation change the shape of the triangle:</u> This option is correct as both dilation and rotation are rigid transformations that do not alter the shape of the triangle (a triangle remains a triangle only with different side lengths)
<u>6- </u></span><u>The rotation reduces the size of the triangle:</u> This option is incorrect as rotation does not alter the size of the shape. It only changes its position