**HOW THE CONTROLS WORK** Click and drag points A and C to manually determine if you can make a triangle. click "random x" to set x to a random location along BC. click "current position" to reshow information about the current location. click "X=..." to set x to a desired position along BC in percents. click "probability" to generate a list of x positions and analyze them for percent possible vs. not possible. click "proof via circles" to draw circles and find the intersecting points and finally, use the up and down arrow keys to change the line color. :P Note that this is not entirely bug free. many features don't work correctly online. Downloading it is and running it in Scratch is recommended.