Activity
- Click on the link that says "Discovering Sine, Cosine and Tangent" at the top of the page.
- Move the green slider to change the measure of the angle. As you change the angle measure what happens to the sides of the triangle?
- Next, create table and record the values of the side lengths and the values for sine, cosine and tangent for three different angles. As you do this, write down how you got from the side lengths to the specific trigonometric values.
- Use the table from the previous question to make a conjecture about how you would find these three functions for any acute angle in a right triangle, include a diagram to explain your rules.
- Make an observation about how these three functions are related to each other.
- Now, move point D at the bottom of the applet and notice what happens to the triangle. Make a conjecture about how this change affects the calculation of the three trigonometric functions.
Teachers may help students who are struggling to find the ratios by either having them create a table for more than three angles or by asking them open ended questions that lead students to making the connection that they are dividing different sides of the triangle to get the different trigonometric functions.