Lesson 14

There is an equilateral triangle, \(ABC\), inscribed in a circle with center \(D\). What is the smallest angle you can rotate triangle \(ABC\) around \(D\) so that the image of \(A\) is \(B\)?

\(60^\circ\)

\(90^\circ\)

\(120^\circ\)

\(180^\circ\)

Which segment is the image of \(AB\) when rotated \(90^\circ\) counterclockwise around point \(P\)?

Here are 2 polygons:

Select all sequences of translations, rotations, and reflections below that would take polygon \(P\) to polygon \(Q\).

Rotate \(180^\circ\) around point \(A\).

Translate so that \(A\) is taken to \(J\). Then reflect over line \(BA\).

Rotate \(60^\circ\) counterclockwise around point \(A\) and then reflect over the line \(FA\).

Reflect over the line \(BA\) and then rotate \(60^\circ\) counterclockwise around point \(A\).

Reflect over line \(BA\) and then translate by directed line segment \(BA\).

1. Draw the image of figure \(ABC\) when translated by directed line segment \(u\). Label the image of \(A\) as \(A’\), the image of \(B\) as \(B’\), and the image of \(C\) as \(C’\).
2. Explain why the line containing \(AB\) is parallel to the line containing \(A’B’\).

There is a sequence of rigid transformations that takes \(A\) to \(A’\), \(B\) to \(B’\), and \(C\) to \(C’\). The same sequence takes \(D\) to \(D’\). Draw and label \(D’\):