Unit 1, Lesson 1

Moving in the Plane

Grade 8

1.1

Warm-up

Which Three Go Together: Diagrams

Which three go together? Why do they go together?

Two rays starting from a point. The two rays point in opposite directions. — A

Two rays starting from a point. One ray extends downward and to the right and the other ray extends upward and to the right. The two rays appear to form a right angle. — B

Two rays starting from a point. One ray extends downward and slightly to the left and the other ray extends downward and slightly to the right. The two rays appear to form an acute angle. — C

Two rays starting from a point. One ray extends upward and to the left and the other ray extends directly downward. The two rays appear to form an obtuse angle. — D

1.2

Activity

Triangle Square Dance

Your teacher will give you three pictures. Each shows a different set of dance moves.

Arrange the three pictures so you and your partner can both see them right way up. Choose who will start the game.
- The starting player mentally chooses A, B, or C and describes the dance to the other player.
- The other player identifies which dance is being talked about: A, B, or C.
After one round, trade roles. When you have described all three dances, come to an agreement on the words you use to describe the moves in each dance.
With your partner, write a description of the moves in each dance.

Are You Ready for More?

Student Lesson Summary

Here are two ways for changing the position of a figure in a plane without changing its shape or size:

Sliding or shifting the figure without turning it. Shifting Figure A to the right and up puts it in the position of Figure B.

A figure that has been slid or shifted in the plane without turning it.

Turning or rotating the figure around a point. Figure A is rotated around the bottom vertex to create Figure C.

A figure that has been turned or rotated around a point

Glossary

vertex

A vertex is a point where 2 or more edges meet. When there is more than 1 vertex, they are called vertices.

The vertices of this polygon are labeled , , , , and .

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Gradeband

Course

Unit

Lesson

Settings

Language

Audience

Assessment Access

Moving in the Plane

Warm-up

Which Three Go Together: Diagrams

Activity

Triangle Square Dance

Are You Ready for More?

Student Lesson Summary

Glossary

vertex

Have a correction or suggestion?

Are You Ready for More?