Illustrative Mathematics - Geometry - Mathematics - Unit 1 - Lesson 21

The triangles here are each obtained by applying rigid motions to triangle 1. Which triangles are translations of triangle 1? Explain how you know.Which triangles are not translations of triangle 1? Explain how you know.

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G.CO.1

G.CO.9

The quadrilateral is a parallelogram. Find the measure of angles 1, 2, and 3.

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G.CO.1

G.CO.9

Angle BDE is congruent to angle BAC. Name another pair of congruent angles. Explain how you know.

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G.CO.1

G.CO.9

Describe a transformation that could be used to show that corresponding angles are congruent.Describe a transformation that could be used to show that alternate interior angles are congruent.

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G.CO.1

G.CO.9

Lines AD and EC meet at point B.Which of these must be true? Select all that apply.

• A 180 degree clockwise rotation using center B takes D to A.
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• {"blocks":[{"key":"82j02","text":"Angle ABE is congruent to angle ABC.","type":"unstyled","depth":0,"inlineStyleRanges":[{"offset":6,"length":3,"style":"BOLD"},{"offset":32,"length":3,"style":"BOLD"}],"entityRanges":[],"data":{}}],"entityMap":{}}

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G.CO.1

G.CO.9

Points E, B, and C are collinear. Explain why points A, B, and D are collinear.

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G.CO.1

G.CO.9

Draw the image of figure ACTS after a clockwise rotation around point C using angle CTS and then a translation by the directed line segment CT.Describe another sequence of transformations that will result in the same image.

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G.CO.1

G.CO.9

Triangle ABC is congruent to triangle A'B'C'.  Describe a sequence of rigid motions that takes A to A', B to B', and C to C'.

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G.CO.1

G.CO.9