Related Clues:

• Trig topics
• Figures formed by the intersection of two lines
• They may be obtuse, but they also may be right
• Mostly communicate with one — none is any longer in specific circle
• Lines in circles
• Lines from a circle’s centre to its perimeter
• Head cut from nail with two straight lines
• Awesome, two straight lines
• Protractors measure them
• Pool shot considerations
• "I teach geometry, so I know all the __": math professor's quip