[size=150]Creation of this resource was inspired by [url=https://www.openmiddle.com/perpendicular-lines-and-slope/]this Open Middle problem[/url] from [url=https://twitter.com/Math_m_Addicts]Nanette Johnson[/url]. [br][br][/size][size=150][color=#0000ff][b]How many possibilities exist here? [/b][/color][/size]