Geometry, Teacher\'s Edition

(Axel Boer) #1

5.7 Similarity


Ratios and Proportions


I.SectionObjectives



  • Write and simplify ratios.

  • Formulate proportions.

  • Use ratios and proportions in problem solving.


II.ProblemSolvingActivity-Ratio/ProportionRelay



  • Since this lesson is mostly review, use this fun game to review the concepts in the lesson.

  • To prepare, bring in a bunch of assorted items from home. Make these random household items, but have
    more than one of each type of items. For example, three hairbrushes or five apples.

  • Then put the students are four teams.

  • This activity is timed.

  • Students come up one at a time.

  • Students have 15−20 seconds to look at the table and write as many ratios as they can.

  • Then buzz it and the next person comes up.

  • The last person has to take the ratios of the first three and create as many proportions as he/she can in two
    minutes.

  • Students are not allowed to coach each other in their work.

  • The team with the most ratios earns points.

  • The team with the most correct proportions wins.

  • You can repeat this more than once. Students will love it.


III.MeetingObjectives



  • Students will write and simplify ratios.

  • Students will write proportions.

  • Students will use ratios and proportions in problem solving.


IV.NotesonAssessment



  • How many ratios did each team write?

  • Are the proportions accurate?

  • Assess the time constraints, did the students need more or less time- adjust as necessary.


Properties of Proportions


I.SectionObjectives


Chapter 5. Geometry TE - Problem Solving
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