Micro-teaching 2: Lesson Plan for Sine Law

Title: Learning the different cases of the Sine Law
Date: November 30, 2015
Grade Level: Pre-calculus 11
Prescribed Learning outcomes: ·         Be able to understand how to apply Sine Law to solve problems. ·         Introduce oneself of 3 different cases of triangles in applying the Sine Law.
General purpose: The class will look at how the Sine Law can be used to find the unknown length of the side of a triangle given one angle and the length of the other two sides. We will look at three (3) cases: 1.       Where there is no solution, 2.       Where there is one solution, 3.       Where there are two solutions.
SWBAT 3.5    Sketch a diagram and solve a problem, using the Sine Law. 3.6    Describe and explain situation in which a problem may have no solution, one solution, or two solutions.
Probing of Previous Knowledge ·         The class has already been introduced with the notion of Sine Law (the relationships between the sides and angles) and the proof of Sine Law. ·         The class understands basic properties of triangles and knows how to draw a triangle, such as labelling the angles, sides, and the height, respectively. ·         The class understands the concept of SOH-CAH-TOA; students are expected to know how to calculate the height of a triangle using SOH-CAH-TOA.
Objective	Time	Activity	Materials
Introduction	1 minute	·         Ask students where they see the use of trigonometry in their everyday life. ·         Provide more background info on trigonometry that appeal to them.
Summary	2 minutes	·         Ask students if they can recall what sine law is (just in case not everyone does). ·         Draw a generic, 3-sided triangle. ·         Review the concept of Sine Law. ·         (With a diagram) Ask students if they can find an unknown angle or length of a triangle given the other two lengths and an angle. Is this always possible?	Whiteboard Markers
Inquiry Project	10 minutes The instructor will spend 3 minutes with each group, then rotate for a total of 9-10 minutes.	·         Introduce to class the three (3) different cases of the Sine Law. ·         Divide the class into three groups. Within each group: ·         The instructor presents a different case. ·         The instructor gives each student a set of 3-4 sticks, where students have to make as many different triangles as they can think of. ·         Once students are finished making their answers, they have to explain their answers to the group. ·         The instructor will help to guide the students, writing the problem on the board and explaining why there is indeed only one, two, or no solution.	Measured sticks with which to make triangles. Multiple sets for each of the three cases.
Handout + Summary	3 minutes	·         Provide the class with handout on the three cases of Sine Law. ·         Go over the handout briefly. ·         Use it to show students that the three different cases necessarily have one, two, or no solutions. ·         Illustrate this on the whiteboard. ·         Show the implications of this when solving the Sine Law.	Students may need pen and paper for this.
Summary Evaluation: By having the students learn from doing hands-on activities with the sticks (and other visual tools), they can understand better the numbers of triangles that can be made given certain angles and lengths.