Activity Overview
In this activity, students explore a right angled triangle and its trigonometric concepts. They investigate the trigonometric ratios for the angles of the triangle.
Before the Activity
Install the Cabri™: Jr. App on the students' graphing calculators using one of these two methods:
TI-Connect™, a TI Connectivity Cable, and the Unit-to-Unit Link Cable
TI-Navigator™ "send to class" feature
See the attached PDF file for detailed instructions for this activity
Print pages 57 - 60 from the attached PDF file for your class
During the Activity
Distribute the pages to the class.
Follow the Activity procedures:
Construct a right triangle
Measure the side lengths and all interior angles of the triangle
Calculate the ratio of the opposite side to the hypotenuse for the acute angles of the triangle
Calculate the ratio of the adjacent side to the hypotenuse for the acute angles of the triangle
Calculate the ratio of the opposite side to the adjacent side for the acute angles of the triangle
Calculate the sin, cos, and tan values for the acute angles
Observe that the sin of an angle is the ratio of the opposite side to the hypotenuse, the cos of an angle is the ratio of the adjacent side to the hypotenuse, and the tan of an angle is the ratio of the opposite side to the adjacent side
Alter the triangle and verify if the relationships hold true
Note that the sin of one angle equals the cos of the other angle
Increase the measure of one of the acute angles
Notice that as the angle gets larger, its sin and tan get larger, whereas cos gets smaller
After the Activity
Review student results:
As a class, discuss questions that appeared to be more challenging
Re-teach concepts as necessary