Vertical Angles Discovery
DIRECTIONS:
Please do the following:
1) Use the LINE tool 
to construct 2 lines that intersect.
2) Use the INTERSECT tool 
to plot the point at which these 2 lines intersect.
3) Use the ANGLE tool 
to measure any 2 angles that are not adjacent each other. When you use this tool, you will click the THREE Points that form the Angle, as if you were naming it. Remember, VERTEX goes in the middle.
to construct 2 lines that intersect.
2) Use the INTERSECT tool to plot the point at which these 2 lines intersect.
3) Use the ANGLE tool to measure any 2 angles that are not adjacent each other. When you use this tool, you will click the THREE Points that form the Angle, as if you were naming it. Remember, VERTEX goes in the middle.4)
What do you notice?
When you're done (or if you're unsure of something), feel free to check by watching the quick silent screencast below the applet.