1. Graph the equation for the unit circle: [math]x^2+y^2=1[/math][br]2. Click on the GEOMETRY button. [br]3. Click on the POINT tool. Add three points:[br] One point at the origin (0,0)[br] Another point at (1,0)[br] A third point anywhere on the circle (This point is VAL)[br]4. Click on the SEGMENT tool. Draw the radius from the center (0,0) to the point on the circle (VAL).[br]5. Click on the ANGLE tool. Create the standard position angle by selecting the three points in order[br] (1,0) then (0,0) then VAL [br]6. Click on the CALCULATOR button. Rename the point on the circle as VAL.[br]7. Click on the three dots next at the end of the line. Click on SHOW LABEL.[br] Drag VAL around the circle. Her standard position angle should change as she travels around the circle.

1. Drag VAL into quadrant I[br]2. In the INPUT line, type: [b]X=(x(VAL),0). [/b][br] A point should appear on the x-axis, directly under VAL.[br]3. In the INPUT line, type: [b]h=segment(VAL,X).[br][/b]4. Select the input line for h. [br] Click on the three dots at the end of the line. [br] Under [b]SHOW LABEL[/b], select [b]NAME & VALUE.[/b][br]4. Drag Val. Her angle and her height should change as you drag her around the unit circle.[br]

1. Drag VAL back to quadrant I. [br]2. Click on the Geometry Button.[br]3. Click on the [b]POLYGON[/b] Button. Click on the points in this order:[b] VAL, Origin, X, VAL[/b][br] A shaded right triangle should be formed.[br]5. Click on the [b]REFLECT ABOUT LINE[/b] button. [br] Click in this order: [b]VAL, then the shaded triangle, then the y-axis. [/b][br] A reflection of the triangle should appear in Quadrant II.[br]6. Now click in this order: [b]VAL, then shaded triangle, then x-axis.[br][/b] A reflection of the triangle should appear in Quadrant IV.[br]7. Create the mirror-image in Quadrant III (you figure out how!)[br]You should now have 4 congruent triangles, all mirror-images across the respective axes. [br]If you drag VAL, you should see all four triangles change too.