Learners will need: 
A protractor (a small, transparent plastic one is what I recommend)
A ruler 
A graphing or scientific calculator that can perform trigonometric functions and their inverses (If you are looking for a recommendation, a TI-30X IIS is what I personally prefer, but other scientific or graphing calculators will work just as well)

To make a clinometer for Session 3, you will need: 
A straw
Clear tape
String (must be flexible and relatively thin....cotton string that is a thickness somewhere between thread and twine is best -- I will show examples in the first class!)
A metal washer 

Handouts and homework will be provided. Learners will need the ability to download and print PDF documents from the Outschool Classroom. 

Learners will not need to use any apps or websites beyond the standard Outschool tools.

Learners should take this course after Algebra 1 and *at least* a quarter of high school level Geometry.  Typical learners will probably find this unit most useful toward the end of high school geometry, or just after it. Before enrolling, learners should have a solid understanding of topics such as The Pythagorean Theorem, similar triangles, ratios and proportions and solving algebraic equations.