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Geometry 9-2 Complete Lesson: Reflections

By Matt Richardson
Last updated about 3 years ago
21 Questions
Note from the author:
A complete formative lesson with embedded slideshow, mini lecture screencasts, checks for understanding, practice items, mixed review, and reflection. I create these assignments to supplement each lesson of Pearson's Common Core Edition Algebra 1, Algebra 2, and Geometry courses. See also mathquest.net and twitter.com/mathquestEDU.

Solve It! Look at the shapes at the right. Visualize flipping each shape across its yellow line. What word do the images of the shapes form?

Use this link to access a Google Drawing for the Solve It! Use the Google Drawing to flip each shape across the the yellow segment. Doing so will create a word.

Screenshot your final product and upload it to the canvas.

Problem 1 Got It?

Problem 2 Got It?
1. Copy △ABC from Problem 2 to the coordinate plane on the canvas in black. Label A, B, and C.
2. Graph and label the following translation in blue or green.

Problem 4 Got It? Can you use properties of reflections to prove that △GHJ is equliateral?

Problem 4 Got It? Explain your response to the previous item.

Graphing: Graph the following translation of △FGH.
Label F', G', and H'.

Vocabulary: What is the relationship between a line of reflection and a segment joining corresponding points of the preimage and image?

Error Analysis: A classmate sketched this diagram to represent the translation below.
Explain your classmate's error.

Error Analysis: Show and label the correct location of A' on the canvas using blue or green.

Vocabulary: Use reflection notation to indicate the reflection of P(x, y) across the y-axis and the coordinates of the post-reflection imageP'.

Review Lesson 9-1: Consider the translation of point T.
Write a rule to describe the translation represented by the ordered pairs.

Review Lesson 7-2: A map of Alberta, Canada uses the scale 1 cm = 25 km. On the map, the distance from Calgary to Edmonton is 11.1 cm. How many kilometers apart are the two cities? Enter only a number, rounded to the nearest kilometer.

Preview Lesson 9-3: Draw the angles on the protractors using the indicated colors.

Vocabulary Review: △ABC is congruent to △RST and △ABC ≅ △RST. Match corresponding parts of the triangles below.

  • ∠A
  • ∠T
  • ∠B
  • segment AB
  • segment ST
  • segment TR
  • ∠R
  • ∠C
  • ∠S
  • segment CA
  • segment BC
  • segment RS

Use Your Vocabulary: Tell whether the pair of figures shows a reflection.

Use Your Vocabulary: Tell whether the pair of figures shows a reflection.

Use Your Vocabulary: Reflect △ABC over the line segment. Draw and label its reflection, △A'B'C', in blue or green.

Reflection: Math Success