For this activity, we wanted an applet that would give the students practice while also allowing them to solidify their understanding of how the vertex and the distance between the focus and directrix relate to the equation of a parabola. Since the standard asks students to derive the equation of a parabola given a focus and a standard, these relationships are the building blocks required for students to be able to do this.
The point of using an applet to do this instead of giving the student a worksheet is so that the student can receive immediate feedback from Khan Academy as to whether their answer is correct or not. If the student gets the first answer incorrect, it would be disheartening. However, it wouldn't be nearly as disheartening as getting a worksheet back with 5 problems on it, and be told that they got 5 of the 5 problems incorrect. The applet also has a "show hint" feature that the students can utilize if they are too afraid to ask the instructor for help.
The point of using an applet to do this instead of giving the student a worksheet is so that the student can receive immediate feedback from Khan Academy as to whether their answer is correct or not. If the student gets the first answer incorrect, it would be disheartening. However, it wouldn't be nearly as disheartening as getting a worksheet back with 5 problems on it, and be told that they got 5 of the 5 problems incorrect. The applet also has a "show hint" feature that the students can utilize if they are too afraid to ask the instructor for help.