That will grab them and bring them into the discussion. Just think of the importance and impact of this lesson. If they do not clearly understand the properties of right triangles and the Pythagorean Theorem they can't even begin to learn trigonometry. Do you have to show a football related video? No! There are plenty of videos on this topic that relate to all kinds of topics from designing a house to a dirt bike ramp.
The bottom line is be creative don't lose the class before you even start the lesson. This is one of the lessons in Geometry that has endless possibilities when it comes to creativity in the class room. Give them something memorable to recall so that when you teach them the Unit Circle
they don't have to memorize the whole thing because they lack these basic skills. For tips on teaching the Unit Circle: Click Here
Editable Materials to Use with this Lesson
(You must be a member to gain access to these materials)