options: Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. For example, arrange three copies of the same triangle so that the sum of the three angles appears to form a line, and give an argument in terms of transversals why this is so.

Understand that a two-dimensional figure is similar to another if the second can be obtained from the first by a sequence of rotations, reflections, translations, and dilations; given two similar two-dimensional figures, describe a sequence that exhibits the similarity between them.

Verify experimentally the properties of rotations, reflections, and translations:
- Lines are taken to lines, and line segments to line segments of the same length.
- Angles are taken to angles of the same measure.
- Parallel lines are taken to parallel lines.

Understand that a two-dimensional figure is congruent to another if the second can be obtained from the first by a sequence of rotations, reflections, and translations; given two congruent figures, describe a sequence that exhibits the congruence between them.

Describe the effect of dilations, translations, rotations, and reflections on two-dimensional figures using coordinates.
problem_activity: Problem 1
Figure 1 (F1) and Figure 2 (F2) are shown below. For each statement below, determine if it is true or false. Explain your reasoning.
[IMG]
a.   A reflection over the
$$x$$
-axis and a translation to the left will transform F1 to F2, making the two figures congruent.
b.   A rotation of
$${180^{\circ}}$$
about the origin will transform F1 to F2, making the two figures congruent.
c.   A dilation from the origin and a translation up will transform F1 to F2, making the two figures similar.
d.   A reflection across the
$$x$$
-axis and a reflection across the
$$y$$
-axis will transform F1 to F2, making the two figures congruent.
e.   There is no sequence that will transform Figure 1 to Figure 2, making the two figures neither congruent nor similar.
Problem 2
The pentagon shown below is the resulting image of pentagon
$${ABCDE}$$
after it was dilated from point
$$A$$
by a scale factor of
$${\frac{1}{2}}$$
and then rotated clockwise
$${90^{\circ}}$$
about point
$$A$$
.
What are the original coordinates of pentagon
$${ABCDE}$$
?
[IMG]


correct_option_index: 1

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