4.7 Similarity
Ratios and Proportions
I.SectionObjectives
- Write and simplify ratios.
- Formulate proportions.
- Use ratios and proportions in problem solving.
II.MultipleIntelligences
- Differentiate this lesson by providing opportunities to expand each example for the students. This will provide
students with a way to practice the concepts as the information is presented. - Ratio is a fraction that compares two things.
- Three ways to write a ratio. As a fraction, with a colon or using the word to.
- Expand Example 1: What is the ratio of everything bagels to sesame bagels?
- Answer:^5025 =^21
- Expand the equation example with the dancers and the singers.
- “What if the ratio of dancers to singers was 5 to 4 and there were forty- five dancers? How many singers are
there? How many dancers are there? - Answer: 5n=dancers
- 4n=singers
- 5n+ 4 n= 45
- 9n= 45
- n= 5
- 5( 5 ) =25 dancers
- 4( 5 ) =20 singers
- Proportion- an equation that compares two equal ratios.
- Expand Barn Dimensions example.
- “What if the water line was actually 20 ft instead of ten? What would the length be on a scale drawing?”
- Answerx=5 inches
- Intelligences- linguistic, logical- mathematical, visual- spatial
III.SpecialNeeds/Modifications
- Write each definition and its examples on the board. Request students write down the information in their
notebook. - Explain the Cross Multiplication Theorem as something that the students already know from previous classes
about how to solve a proportion. This is a formal way of writing it.
IV.AlternativeAssessment
- Throughout the expansion of each exercise, allow students to contribute their answers to class discussion.
Chapter 4. Geometry TE - Differentiated Instruction