21st Century Integration Model

Title: Non-Right Angle Trigonometry
Subject: Mathematics
Grade Level: 9 through 12

Lesson Summary

NCTM Illuminations' unit on Law of Sines and Law of Cosines provides students with the knowledge of finding side length and angle measure of non-right triangles. To assure each student has developed an understanding of non-right triangle trigonometry, have students develop a multimedia presentation, including an introduction slide describing the Law of Sines and Law of Cosines; an ASA (or AAS) problem, SSA problem, SSS problem, and SAS problem for determining the missing sides or missing angles; and a conclusion slide for a comparison of the laws.

Original Lesson Plan

Law of Sines and Law of Cosines — http://illuminations.nctm.org/LessonDetail.aspx?ID=U177

Original Objectives

Students will:

  • Use right triangle trigonometry to develop the law of sines.
  • Use the law of sines to solve problems.
  • Use right triangle trigonometry to develop the law of cosines.
  • Use the law of cosines to solve problems.

21st Century Skills Integration Objective(s)

Students will demonstrate ICT Literacy skills by developing a slide-show presentation on non-right triangle trigonometry. Students will demonstrate critical thinking skills by analyzing the Law of Sines and the Law of Cosines. Students will demonstrate problem solving skills by developing non-right triangle trigonometry problems and by showing their work for solving those problems.


  1. Before Lesson: Download and install OpenOffice on students' computers (or use Microsoft PowerPoint if it already exists on the student computers).
  2. During Lesson: Instruct students to develop four non-right triangle trigonometry problems: ASA (or AAS), SSA, SSS, and SAS. Also, have the students brainstorm on the comparison of the Law of Sines and the Law of Cosines.
  3. In OpenOffice, students will access Impress to begin work on their multimedia presentation that will include six slides.
  4. Students will create an introduction slide for the Law of Sines and the Law of Cosines. This slide will include necessary background information on the laws.
  5. Students will create one separate slide for each of their non-right triangle trigonometry problems (four total). Each of these slides will provide step-by-step solutions to their problems, and each slide will include a title that describes whether they are solving an ASA, SSA, SSS or SAS problem.
  6. Students will create a conclusion slide on the comparison of the laws. At this time, students will use their critical thinking skills to analyze the laws.