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Lesson Plans and Worksheets for Grade 8

Lesson Plans and Worksheets for all Grades

More Lessons for Grade 8

Common Core For Grade 8

Examples, videos, and solutions to help Grade 8 students how to reflect a figure and learn the basic properties of reflection.

### New York State Common Core Math Grade 8, Module 2, Lesson 4

Worksheets and solutions for Common Core Grade 8, Module 2, Lesson 4

Student Outcomes

2. Which figure(s) were not moved to a new location on the plane under this transformation?

3. Reflect the images across line L. Label the reflected images.

4. Answer the questions about the previous image.

a. Use a protractor to measure the reflected ∠ ABC

b. Use a ruler to measure the length of image of IJ after the reflection.

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

Lesson Plans and Worksheets for Grade 8

Lesson Plans and Worksheets for all Grades

More Lessons for Grade 8

Common Core For Grade 8

Examples, videos, and solutions to help Grade 8 students how to reflect a figure and learn the basic properties of reflection.

Student Outcomes

• Students know the definition of reflection and perform reflections across a line using a transparency.

• Students show that reflections share some of the same fundamental properties with translations (e.g., lines map to lines, angle and distance preserving motion, etc.).

• Students know that reflections map parallel lines to parallel lines.

• Students know that for the reflection across a line L, then every point P, not on L, L is the bisector of the segment joining P to its reflected image P'.

Lesson Summary

A reflection is another type of basic rigid motion.

Reflections occur across lines. The line that you reflect across is called the line of reflection.

When a point, P, is joined to its reflection, P', the line of reflection bisects the segment, PP'.

Concept Development

Exercises

1. Reflect triangle ABC and Figure D across line L. Label the reflected images.2. Which figure(s) were not moved to a new location on the plane under this transformation?

3. Reflect the images across line L. Label the reflected images.

4. Answer the questions about the previous image.

a. Use a protractor to measure the reflected ∠ ABC

b. Use a ruler to measure the length of image of IJ after the reflection.

5. Reflect Figure R and triangle EFG across line L. Label the reflected images.

Basic Properties of Reflections:

(Reflection 1) A reflection maps a line to a line, a ray to a ray, a segment to a segment, and an angle to an angle.

(Reflection2) A reflection preserves lengths of segments.

(Reflection 3) A reflection preserves degrees of angles.

If the reflection is across a line L and P is a point not on L, then L bisects the segment PP’, joining P to its reflected image P’. That is, the lengths of OP and OP’ are equal.

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You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

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