Subject
Grade
Big Idea
Trigonometry involves using proportional reasoning to solve indirect measurement problems.
Elaboration
- comparisons of relative size or scale instead of numerical difference
- using measurable values to calculate immeasurable values (e.g., calculating the width of a river using the distance between two points on one shore and an angle to a point on the other shore)
- Sample questions to support inquiry with students:
- How is the cosine law related to the Pythagorean theorem?
- How can we use right triangles to find a rule for solving non-right triangles?
- How do we decide when to use the sine law or cosine law?
- What would it mean for an angle to have a negative measure? Identify a context for making sense of a negative angle.
keywords
proportional reasoning
indirect measurement