- Observe students through this lesson.
- Allow plenty of time for the students to ask questions.
- Repeat examples or information that seems unclear.
Acute and Obtuse Triangles
I.SectionObjectives
- Identify and use the Law of Sines.
- Identify and use the Law of Cosines.
II.MultipleIntelligences
- There is a lot of information in this chapter. I recommend breaking it down and going through the examples
slowly so that students are given a visual aid, an auditory aid and a chance to verbally ask questions. - Intention of lesson- to apply the sine and cosine ratios to angles in acute and obtuse triangles.
- Law of Sines- is constant. It can be used to find the missing lengths in triangles.
- Review using a calculator to find the value of sines.
- Law of Cosines- works on acute, obtuse and right triangles.
- If the students seem lost during this lesson, break them up into small groups. Assign each group either the
Law of Sines or the Law of Cosines and have them create a poster explaining the steps to using these laws in
an example. - The students can even use one of the examples in the text.
- By having the students create a poster to explain the information, the students will learn to assimilate the
information themselves. - Allow time for each group to explain their poster when finished.
- Intelligences- linguistic, logical- mathematical, visual- spatial, interpersonal, intrapersonal
III.SpecialNeeds/Modifications
- Begin with a review of sines and cosines.
- Allow time for student questions.
- Review acute triangles have all angles that are less than 90.
- Review that obtuse triangles have one angle that is greater than 90.
- Review using a calculator to find the value of sines.
IV.AlternativeAssessment
- Walk around while the students are working on their posters.
- Listen to the conversation in the groups.
- Are the students on task? Are they having difficulty?
- Often if the conversation has strayed from the content of the assignment, the students are lost and not sure
what to do next. - Assess student understanding through posters and presentations. Clarify points that have been missed or are
incorrect.
4.8. Right Triangle Trigonometry